Power-Saving Web Pages: Real Or Myth?

An anonymous reader writes "Are dark webdesigns an energy saving alternative to a snow white Google? The theory is websites with black backgrounds save energy, based on the assumption that a monitor requires more power to display a white screen than black. Is this a blatant green washing ploy by Blackle.com, or an earnest energy saving tweak for a search tool we use every day? To find out, PCSTATS hooked up an Extech Power Analyzer to a 19" CRT and a 19" LCD and measured power draw — turns out there is a not insignificant difference ..."

Comments

even more savings

[ch-chuck]

s/not insignificant/significant/
will save another few picowatts drawing 6 redundant characters.

Re:even more savings

[Seraphim1982]

But the characters are black, so each one represents energy saved.

Re:even more savings

[cayenne8]

Thank you.

My first question after reading the synopsis was, "Does anyone really fucking CARE about this?"

I mean..this is minutiae.....

Re:even more savings

[Anonymous Coward]

This is about "The Cosby Show " isn't it?

Re:even more savings

[crutchy]

lol "s/not"... yeah i'm tired

i'm pretty sure black uses more energy in lcds than white, because the power is used to mask light, not generate it, so a completely white screen might save more power in modern screens than black, though i don't know about more modern technologies like tft. new led screens are probably also opposite, so any power-saving web page would have to detect the type of screen (lcd or led)

Re:even more savings

[Gadget_Guy]

Does anyone really fucking CARE about this?

Obviously you care, otherwise you would not have clicked on the "Read More" link on the story, then replied to the first post to get you to the top of the page, and then typed a message about this subject. The alternative to all this would have been to just skip to the next story that does interest you.

At time of writing, there have been nearly 200 posts on this story, so the answer to your question is yes, some people do care enough to think about this subject.

Re:even more savings

[Anonymous Coward]

Agreed. Of the top 20 things web sites are optimized for, this will be #21. Or of the top 100 things web sites are optimized for, this will be #101. And so on, all the way down to the bottom turtle (note: there is no bottom turtle).

Re:even more savings

[Tassach]

this is minutiae.....

3.8W is hardly a minute amount of power. If I did my math right, it's approximately the amount of power it takes to lift a full soda can (~390g) 1 meter in 1 second.

Let's say each Google query takes 10 seconds of viewing time, so you could save 38 watt-seconds per query by going black. Multiply this by 3 Billion queries per day, times 365 days/year. That's 12GWh (to 2 significant figures) of electricity that could be saved annually by changing a couple lines of code.

Power costs around $0.10/KWh. I don't consider $1.2M/year to be a minute amount of money.

Re:even more savings

[Golddess]

Maybe it's just me, but I would not call "not insignificant" the same as "significant". For example, using some numbers pulled out of no where, 10% would be not insignificant, but it wouldn't be significant until it reached >=90%.

Re:even more savings

[rev0lt]

(...)of electricity that could be saved (...)

Saved as in not paid directly. Electricity won't suddenly stop being produced because the average consumption dropped a few KWh, and this is one of the most ignored factors by "the green people". Electricity is generated regardless and must be spent almost immediatly - there is no efficient way of storing it (and no, batteries aren't that efficient), specially when considering the sheer requisites of the high values (both voltage and current) involved.
That said, it's always good for the consumers to save a few cents. But take it for what it is (a money question) and not as an "environment-friendly" approach.

Re:even more savings

[rev0lt]

Many modern lcd screens have dynamic contrast, so inefficient dimming of the backlight can be blamed for the differences measured. Also, most LCD panels implement tricks for color composition (specially those so-popular-so-fast 6 bit TN panels), so additional processing may be done on specific colors/tones, and that could explain the increased consumption.

Re:even more savings

[Anonymous Coward]

Something is either significant or it isn't. I think you are confusing "significant" with something like "majority" or "overwhelming". Significant means "important". Insignificant mean "unimportant". You are arguing that something can be neither important nor unimportant.

Re:even more savings

[amoeba1911]

No. The amount of fuel your power plant uses is proportional to the power it is supplying. In case of coal plant: there is less coal being burned, in case of hydroelectric: less water needs to go through the turbines, in case of nuclear: control rods are inserted into the reactor core to slow down the reaction of the fuel rods by absorbing neutrons.

Less power used = less power generated = less fuel used.

Re:even more savings

[Anonymous Coward]

Google query takes 10 seconds of viewing time, so you could save 38 watt-seconds per query by going black.

I agree, Google should do this and not go back.

Re:even more savings

[DustPuppySnr]

I don't consider $1.2M/year to be a minute amount of money.

Any number can look impressive without context.
Let's divide that impressive $1.2M per year by 12 months and then by the 1 billion uniques that Google is getting per month. This will give you the grand total of a fraction of a cent per user per month saving.
And seeing that this is distributed globally, there is no power plant that will see any significant drop in power generation even if the whole world switch over.

Re:even more savings

[Anonymous Coward]

Because there is no efficient way of storing energy, energy companies constantly adjust the total generator output to be as close to demand as possible. They even have special fast-startup generators to handle sudden spikes in energy demand. In other words, if demand goes down, then energy is really saved, no question about it.

Re:even more savings

[neyla]

Sorry, but that's as they say "not even wrong". When demand drops, you can produce at less than peak. This saves fuel in a heat-based powerplant, and reduces water-consumption in a hydro-power one. That fuel or water *does* trivially store for months or even years.

Produced electricity stores poorly, but you don't do that.

Re:even more savings

[Jappus]

And seeing that this is distributed globally, there is no power plant that will see any significant drop in power generation even if the whole world switch over.

I think you'd have fit in great as an ancient greek philosopher. After all, according to no one less than Aristotle:

"In a race, the quickest runner can never overtake the slowest, since the pursuer must first reach the point whence the pursued started, so that the slower must always hold a lead."
and
"If everything when it occupies an equal space is at rest, and if that which is in locomotion is always occupying such a space at any moment, the flying arrow is therefore motionless."

This is the same flawed logic you are using. The fast runner DOES overtake the slow runner eventually, because even though you can split their progress into infinitely small amounts of space, you also split the time needed to cross that distance. As such, at some finite point in time, the distance between the two runners will be 0 and then grow in favour of the faster runner. It does not matter that you can theoretically split space infinitely often, as you must also always split time in the same manner.

And equally, the arrow moves eventually to its target, because even though you can split time into theoretically arbitrarily small chunks and thus eventually reduce the speed of the arrow per infinitely small time slice to 0, you split the space covered in the slice just as much. As such, you will reach any finite point in space (assuming the arrow is not stopped by something) in finite time. Again it does not matter than you can theoretically split time, because you need to split space at the same time.

So the same applies in your example. Yes, you can theoretically increase the number of times you split the saved power infinitely often, but to do so, you also have to increase the number of users infinitely often. As such, you will by summing it all up arrive at a non-zero amount of power saved in total. As you know from the laws of thermodynamics, you can't destroy energy. So the saved energy must be stored in some form or another. You can "waste" it by turning it into excess heat, or you can store it for later in a more accessible form, or not liberate it to begin with from its initial high-potential state (as coal, nuclear fuel, wind, water, etc.).

Simply put: Knowledge about the principles of infinities and successive splits has increased dramatically since ancient Greece.

Re:even more savings

[umghhh]

not entirely true - characters are black so more characters means less white space on your display and this is less energy dissipated trough your laptop int environment.

Re:even more savings

[Anonymous Coward]

You are arguing that something can be neither important nor unimportant.

And that would be correct. A piece of information can certainly be neither important nor unimportant. In the English language "significant != not insignificant" - they are different words with subtly different meanings, not the opposite of each other.

Re:even more savings

[allo]

the amount of fuel is constant in my solar power plant, you insensitive clod!

Re:even more savings

[xaxa]

In addition to the points raised by the other replies, if 5W of power can be saved per person -- perhaps by mandating that standby power consumption of home electronics can be reduced -- then in a country of 50M people that's 250MW. That's a small fossil-fuel power plant, or a large wind/solar plant, which no longer needs to be built.

Re:even more savings

[rev0lt]

While hydro is somewhat more dynamic at scaling power than thermal, it's not as easy as you say (duty cycles, base provisioning, etc), and certainly some KWh don't make any difference production-wise. The cost of scaling power in thermal centrals (excluding nuclear ones) is very high - there was an old coal central nearby, and it took a month from igniting a furnace to be ready for electricity production, so, as you may imagine, they did not turned them off each time consumption dropped.
There also also technical factors to why it is a bad idea to produce electricity near the average consumption level - One of them is that most electrical equipment tend to deteriorate under stress, so having a safe production margin minimizes transformer damage and conductor damage.

Re:even more savings

[rev0lt]

The amount of fuel your power plant uses is proportional to the power it is supplying.

Only to a certain extent. You don't turn on and off furnaces on a coal/gas plant just because demand dropped. Most of those plants burn fuel (a ton of it) regardless of their production being in active use or not.
Hydro plants are more dynamical, but you still have a baseline water consumption value (the minimum needed to keep a turbine working), and turning them on and off isn't instantaneous either. Most hydro generation is done in dams, so you usually need to maintain a minimum flow of water (usually enough to generate electricity) regardless of electricity consumption. Again, a few KWh won't make a difference.
I'm not familiarized with the nuclear powerplants, but I'd guess they are somewhat similar to hydro.

Re:even more savings

[ceoyoyo]

"I don't consider $1.2M/year to be a minute amount of money."

That's pretty minute, when it considers every single Google query.

Re:even more savings

[Eraesr]

The sentence is just odd to begin with.
There is a not insignificant difference? So there is a difference that is large enough to be considered significant? Or is the author of the summary mistaken and is there a difference, but is it insignificant?

Re:even more savings

[azrael29a]

in case of hydroelectric: less water needs to go through the turbines

Less power used = less power generated = less fuel used.

But water is not used in the same way as coal is. Same amount of water enters and leaves the hydroelectric power plant. It's not destroyed in the process like fossil fuels. Using less energy from a hydroelectric power plant doesn't save water at all.

Re:even more savings

[Guignol]

Yes yes yes, except those paradoxes come from Zeno, not Aristotle. Aristotle was the first one (I think) to try to answer the paradox.

Re:even more savings

[Rysc]

Indeed. Knowing language well and using it carefully allows us to be precise and expressive, and makes talking to dullards frustrating. While the flexibility exists that someone could say "not insignificant" and mean "significant", it is not inherently an opposite and should not be presumed to be opposite.

Re:even more savings

[Golddess]

Bleh... that should have read "<=10% would be insignificant, >10% would be not insignificant, but it wouldn't be significant until it reached >=90%". Though thankfully it looks like the intent still got across.

Re:even more savings

[kurzweilfreak]

Thank you, I was looking for someone who had done the math of savings over this amount of usage. I agree, that amount of savings is hardly trivial. Plus, I hate bright white screens with black text on it, especially at night. It makes my eyes so tired that it's a pain just to keep reading.

Re:even more savings

[rich_hudds]

I never really bought into the idea that the flaw in Zeno's paradox was that he didn't realise you could split time infinitely, or that using calculus you can sum infinitesimals. I reckon it is a pretty good argument if you accept its premises.

Personally I think you have to look to quantum mechanics and the uncertainty principle to find a satisfactory way around it. You can't actually say what precise speed either runner is running at or exactly where they are. Once you factor this in, the assumption that you can split the difference between them into infinitely small steps is just wrong so the paradox disappears.

Re:even more savings

[dj245]

Only to a certain extent. You don't turn on and off furnaces on a coal/gas plant just because demand dropped. Most of those plants burn fuel (a ton of it) regardless of their production being in active use or not.

This is true at a plant-level but is misleading when you consider the whole grid. In many jurisdictions in the US, the different power stations bid on the price of electricity. In a simplified case, if Bob will sell you 100MW at $0.04 and Tom will sell you 80MW at $0.06, but 150MW is needed, then you buy all of Bob's power and then 50MW of Tom's. If the load drops to just 80MW, then you stop buying from Tom altogether, and Tom probably shuts his machine down. There are complications to this scheme including power-purchasing agreements, spinning reserve requirements, etc, but that is basically how it works.

The grid operator knows how much power they will need to within a pretty good margin of error. It is very predictable depending on the outside temperature and the time of day. Most people have a daily routine of electricity use and in the aggregate, the electricity use of a population is very stable and predictable. 10,000 people going home at 5PM and turning on their electric stove is predictable. Large users of electricity are often required to notify the grid operator in advance so a huge machine coming online doesn't cause problems on the grid. So if the grid operator knows they will only need 5GW for the next week (because of cooler temperatures or whatnot) but have 8GW of generating capacity, they give notice to the unneeded stations that they probably won't be buying their power for a while. If nobody is buying your power then you shut the plant down (with the following exceptions).

Hydro plants aren't as restricted in water flow as you might think. Most dams have multiple (even dozens of) turbines so the just shut one down completely. The bigger problem is that they need to keep a certain flow rate because otherwise the downstream river would dry up. This is why hydro plants are usually the cheapest power around when demand is low. The water needs to flow downstream anyway.

Nuclear power stations don't really fit into your argument because they start up, run continuously for months or years, and then shut down for maintenance. Their biggest cost is personnel. Fuel is only a tiny fraction of their expenses so it makes no sense to shut a nuclear machine down unless maintenance is required.

Re:even more savings

[rev0lt]

In many jurisdictions in the US

I have no experience at 3rd word country power grids. And while I may be flaming a bit, doesn't make it less true - the US grid system is crap.

In a simplified case, if Bob will sell you 100MW at $0.04 and Tom will sell you 80MW at $0.06, but 150MW is needed, then you buy all of Bob's power and then 50MW of Tom's. If the load drops to just 80MW, then you stop buying from Tom altogether, and Tom probably shuts his machine down. There are complications to this scheme including power-purchasing agreements, spinning reserve requirements, etc, but that is basically how it works.

That's how it is on the US. Not how it works. The US probably have the shittiest energy regulation of all civilized countries, and it doesn't work. Week-long outages in some regions isn't my definition of "working".

The grid operator knows how much power they will need to within a pretty good margin of error. It is very predictable depending on the outside temperature and the time of day. Most people have a daily routine of electricity use and in the aggregate, the electricity use of a population is very stable and predictable. 10,000 people going home at 5PM and turning on their electric stove is predictable.

Oh yes. You are absolutely right. How does that contradict what I said? It doesn't. Those 10k people could turn the oven on, there would be no spike. Because electricity is already being produced in excess. All those 10k people switching off a lightbulb? (about 5x the savings of white vs black background on an lcd)? No effect. Turning off the PC? no effect.

Hydro plants aren't as restricted in water flow as you might think.

Did I say they were restricted in water flow? What I said is that isn't just throwing a switch and bam! you have power. The most common dams (on small rivers) have usually upto a dozen turbines, but almost never running at capacity. The bigger the turbines, more water they need to work at production levels. But if it rains a lot, you'll have all those dams running at full capacity generating electricity that won't be spent anyway. Also, if it is a navigated river, you'll always keep the water running.

Nuclear power stations don't really fit into your argument

Didn't I said that?

so it makes no sense to shut a nuclear machine down unless maintenance is required.

So why would you be worried with "the environment" and trying to save some KWh if your energy is produced by a nuclear powerplant? Did you actually read what I posted?

Re:even more savings

[rev0lt]

That is whishful thinking. Take the last 10 years as an example - CFL are the most common type of light available, they provide typical 5x savings (we're talking about saving way over those 5W you're trying to save, on an actual common household item that everybody has). Now tell me about all those powerstations that weren't built because CFL savings...

Seriously?

[Cinder6]

Did anyone here actually believe this? The big power draw is from the backlight, which is still running even with black pixels.

Re:Seriously?

[Anonymous Coward]

http://en.wikipedia.org/wiki/Contrast_ratio#Dynamic_Contrast_.28DC.29

Re:Seriously?

[Anonymous Coward]

Seriously? Modern LCDs dim the backlight when the average brightness being displayed is low.

Re:Seriously?

[idontgno]

I bet "Anonymous Reader", our submitter, who probably shills for "blackle.com", "believes" it.

I can't decide if this story is an intentional slashvertisement or an astroturf.

"Blackle.com"? Really? It's only slightly clever to raise the possibility that they're trying to greenwash the issue of "website-specific power consumption", especially since TFS very conveniently refutes that. ("not insignficant?" Sheesh.)

Re:Seriously?

[ColdWetDog]

Did anyone here actually believe this? The big power draw is from the backlight, which is still running even with black pixels.

No, the big power draw is from CRT displays.

Both of them. They'll die someday and things will be nice and green again....

Re:Seriously?

[Shikaku]

Unless the screen is OLED, the answer to "does dark sites save power?" is a flat out NO.

That being said, reading white text on a black background looks a lot better on monitors because the entire background is not light emitting.

Re:Seriously?

[QuasiSteve]

Seriously?
Did anyone here actually believe this? The big power draw is from the backlight, which is still running even with black pixels.

Yes, anyone here actually believed this. I guess in your hurry to post, you misread the double-negative in the summary...

turns out there is a not insignificant difference

...that actually indicates that there is at least a measurable difference.

Note that their measurements apply specifically to the two models they tested, a CRT and a particular LCD.
If 'white' means you have to drive the LCD, then white takes more energy. If 'black' means you have to drive the LCD, then black takes more energy. Most LCD drivers are standardized, though - and given the prevalence of lighter content, it may be worth it to the industry (even if only so they can use it in marketing) to switch the defaults.

Re:Seriously?

[Anonymous Coward]

The link was to pcstats.com, which actually tested the claim. There was a ~25% difference between all-white and all-black screens on their test CRT, and a ~12% difference between the two on their test LCD.

They tested a lot more sites than just Google and Blackle.

Re:Seriously?

[Anonymous Coward]

yes for those few people that still uses CRT theres a slight difference, for LCD the black light is always on so no difference
though there are LCD TVs with back light as a grid of LEDs that can dim individually to increase dynamic range

Re:Seriously?

[betterunixthanunix]

Some monitors will reduce the brightness of the blacklight when the screen displays a very dark image.

Re:Seriously?

[Ferzerp]

You realize that CRTs use less power with darker images for basically the same exact reason?

Re:Seriously?

[Anonymous Coward]

Not to mention the GP post's basic math fail. Even if the backlight (of an LCD) used a constant and "big" amount of power other components of the monitor could vary in power usage. If the values found are between 50-60W then those components could use around 10W and vary from 0-10W (or use 11W and vary from 1-11W, etc) with the backlight using the rest.

In fact the article found power consumption values in the LCD from 38.4W to 34W. Fine, the backlight uses 33W, the other components use between one and 5.4W. The backlight could use 80%+ of the power even if it has a constant power draw. Is that so implausible?

Re:Seriously?

[Xeranar]

I've never understood this argument they had about black bakgrounds. The backlight is always on and hence why we should all be using LED or the newly available translucent monitors that use ambient light. I think the myth is due to our perception of light & dark. We fail to understand black on a monitor is a lack of color and an absorption of all light but the backlight as stated operates independently of the display's image.

Re:Seriously?

[Pentium100]

No, the power draw is from the heaters and the deflection circuitry, but each gun that is turned on at full intensity also adds to the total (that's why full screen yellow uses more power than full screen red or green).

Re:Seriously?

[Yetihehe]

I like reading black on white. With white text on black bg I have afterimages of text lines and this is sometimes rather confusing when trying to read text with another line spacing.

Re:Seriously?

[amicusNYCL]

Unless the screen is OLED, the answer to "does dark sites save power?" is a flat out NO.

How you do figure, where's your data? Their data clearly shows that a CRT displaying all white uses 85W, and the same monitor displaying all black uses 63W, which sounds to me like it's using 25% less power to display the black screen. For an LCD the difference is only about 10%. The grayscale comparisons clearly show a relationship between darkness and power draw.

Re:Seriously?

[Anonymous Coward]

"Pardon" "me"?

Re:Seriously?

[dinfinity]

The LCD they tested is also 8 years old.

I'm not saying newer LCD screens would perform differently (dynamic contrast, local dimming, etc. == marketing stats boosting and terrible) but basing a blanket statement like "B) Websites with darker colours tend to cause the monitor to consume less power." on a test with one LCD monitor is stretching it.

Re:Seriously?

[Anonymous Coward]

I don't think it's as simple as average brightness, as that would seriously fuck up a screen of, say, 95% black pixels and 5% white pixels. I think they basically control brightness by a time-average of the peak brightness, 95th percentile brightness, or some such measure.

Re:Seriously?

[Joce640k]

Did anyone here actually believe this?

I dunno...but I DO know my eyes are funny for a few minutes after I try to read any amount of white-on-black text - it causes massive afterimage.

(Yes, I have the "nostyle" Firefox plugin to deal with these websites)

Re:Seriously?

[Anonymous Coward]

How 'bout reading TFA?! On an LCD it's not relevant, but it *is* on a CRT.

        19" CRT ADI Microscan 19" LCD Samsung 192MP
Google.com 83.5 Watts 38.6 Watts
Blackle.com 65.8 Watts 34.8 Watts
PCSTATS.com 76.2 Watts 37.8 Watts

Re:Seriously?

[tlhIngan]

Did anyone here actually believe this? The big power draw is from the backlight, which is still running even with black pixels.

Actually, it can. Modern LCD displays are crap at this - they employ crap like "local dimming" and "global dimming" to get their stupid contrast ratios. As a side effect, displaying a dark screen does save power because the backlight dims to make the black blacker.

Conversly, displaying a white screen cranks up the backlight to make it brighter, which takes more power.

Since contrast ration is the difference between darkest black and brightest white, this artifically inflates the number. Some monitor specs actually list "dynamic contrast ratio" for this, but it's usually listed as "contrast ratio".

And yes, it's crap. It makes dark images harder to look at because the stuff you want to see is dimmer. And dark stuff on a mostly white screen is harder to look at as well from the retina searing brightness. In an effort to increase global contrast, they reduced local contrast.

Fun fact: a modern TFT display is really like DRAM memory - you have a transistor and a capacitor (the pixel). The only difference is an LCD is write-only electrically, and read-only optically.

If you calibrate your monitor, the first thing you do is turn off auto-dimming because it'll screw up your calibration.

Re:Seriously?

[Anonymous Coward]

Hey idiot, shut the hell up.

Re:Seriously?

[tlhIngan]

Other thing... white on black is hard on the eyes because of "black creep". If you're a typesetter, you know this - if you have light text on dark background, you have to increase the siez of the text in order to keep its apparent size the same. Also, thin fonts sink, so you may have to apply bolding to "fatten" them so they're still legible when the black background slims them down.

Re:Seriously?

[Anonymous Coward]

Ancient shit, being regurgitated. Do it on a plasma and you'll save power. LCD no fucking chance.

Re:Seriously?

[Anonymous Coward]

My TV does this sort of thing. Depends on the screen you have.

If it has 'dynamic power' or 'dynamic dimming' or whatever they call it (turns off parts of the cfl/led) depending on how dark it is. That would save you money. If it does not have that feature you will not notice much. As on is on and 'off' is still on but a 'black' pixel turned on. The power usage for an LCD would be constant (depending on the tech). The power savings is coming from the led/cfl panels.

For a plasma I would bet the power saving isnt too bad there either.

Want real savings? Figure out what the idle off state is. Older ones can draw as much as 20W in the 'off' state. My new 55 inch TV uses less than 1/2W.

Re:Seriously?

[Anonymous Coward]

No, the big power draw is from CRT displays.
Both of them. They'll die someday and things will be nice and green again....

Back in my day the CRTs were green... or sometimes amber.

Re:Seriously?

[John Hasler]

> No, the big power draw is from CRT displays.

> Both of them.

And they are right here in my office, sucking up the gigawatts. They are the reason Wisconsin had no snow this winter. Want to save the environment? Gift me with a couple of 30" LCDs.

Re:Seriously?

[interkin3tic]

Not on my phone (OLED display), where it matters more.

Re:Seriously?

[Anonymous Coward]

I know way too much about printing, but I can't find anything about this "black creep" online, but it sounds exactly like dot gain. Well, except for you thinking it's in people's eyes.

Re:Seriously?

[sunderland56]

The report is internally inconsistent.

• First they state figures for an all-white screen in their "Black and White" test: 85.1W (CRT), 38.4W (LCD).
• Then later they test an all-white screen in their "Greyscales" test: 84.9W (CRT), 40.0W (LCD).

So they show a 1.6 watt difference (LCD) on the same image, where their stated difference between google and blackie is 3.8 watts.

Re:Seriously?

[Anonymous Coward]

"I've never understood this argument they had about black bakgrounds."

I'd not call it an 'argument', we're just missing the 'c'

Re:Seriously?

[Ihmhi]

I am fine with this data being spread and loads of websites switching to white text on a black background. I think it looks cooler, and moreover it is way, way easier to read. Sometimes the white background of a screen just assaults the eyes.

Re:Seriously?

[AmiMoJo]

Have you actually visited blackle.com? It is just a Google search box with a black background. No advertising, no agenda other than someone who seems to have a genuine point.

Even LCDs seem to benefit to the tune of 10% energy savings. 10% over thousands or millions of computers is a lot.

It would be interesting to see stats from more monitors, and also from mobile phones with OLED screens. I have a feeling that the Samsung monitor they tested is one of the smarter ones that reduces blacklight levels when the screen is mostly black, in order to save power and increase contrast a bit (darker dark scenes, brighter bright scenes in movies).

I really don't know why you are so against this. Okay, maybe you prefer white on black... but you seem to hate it just because it's "green". If it makes you feel better it will reduce your electricity bills too.

Re:Seriously?

[Em Adespoton]

This myth started during the days of CRT. I remember when LCD laptops became popular, suddenly everyone started making "white" screensavers etc. to conserve energy -- as the backlight isn't affected by the colors, but a charge is needed for each non-white pixel on the screen.

As such, these days, sites like "blackle.com" are actually WASTING energy by the same logic they claim is saving it. The amount of energy saved is likely minimal, but I DO remember adding some "whitening" CSS to my pages a decade or so ago that did give me ever-so-slightly-more battery life on my laptop. I believe that my CSS probably did this more to the markup it automatically repressed from getting interpreted though, more than from the amount of charged pixels cluttering up the screen real-estate.

Re:Seriously?

[Em Adespoton]

Argh! s/pages/browsers/

Re:Seriously?

[Anonymous Coward]

How many CRT's do you use.... I use a sum total of 0.

Re:Seriously?

[Anonymous Coward]

An LCD uses energy to block the back-light, so a black background actually costs insignificantly more energy.

Re:Seriously?

[Anonymous Coward]

If anything that is stronger support for this conclusion. A newer LCD is more likely to dim that background during dark scenes saving even more energy.

Re:Seriously?

[unjedai]

Yes, anyone here actually believed this. I guess in your hurry to post, you misread the double-negative in the summary...

turns out there is a not insignificant difference

That's why I don't not dislike double negatives.

Re:Seriously?

[rsmith-mac]

How you do figure, where's your data? Their data clearly shows that a CRT displaying all white uses 85W, and the same monitor displaying all black uses 63W, which sounds to me like it's using 25% less power to display the black screen.

True. But really, who's using a CRT these days? Especially with a mobile device or some other method where you're using a battery instead of running off the mains? The fact that the power draw of a CRT changes with the image is technically true, but it's also practically irrelevant since CRT is a dead technology.

Re:Seriously?

[Anonymous Coward]

Try green-on-black. I find that much easier on the eyes.

Re:Seriously?

[biodata]

Not sure if troll. We need to see something to back this up as OP gives stats that show the opposite - black web pages cost less to visit and are more efficient in energy usage than white ones.

Re:Seriously?

[biodata]

Can you back this up? OP measured it and shows stats that show a significant difference.

Re:Seriously?

[biodata]

The only evidence I have seen either way is the evidence in the original article - the displays they tested showed better energy efficiency with black websites than white. Until other evidence comes to light it seems a reasonable hypothesis.

Re:Seriously?

[biodata]

Maybe black on white just gives you such a huge afetrimage you don't regularly notice it? Old-school research showed white on dark blue was easiest on most people's eyes.

Re:Seriously?

[skids]

Heheh.

Actually in the AV space, at least when compared to plasma, they still are "green."

Re:Seriously?

[skids]

I had to be convinced of this as well, when blackle first opened it doors. We tested it with a Kill-A-Watt and had much the same results -- LCDs do use more power on white sites. The reason is Dynamic Contrast features in LCDs.

Re:Seriously?

[amicusNYCL]

What about the power change with the LCD, even though it's less of a change than with the CRT? Is that relevant? Is the takeaway of this article something to do with the popularity of CRTs or something to do with the relationship between brightness and power draw in CRTs and LCDs?

Re:Seriously?

[Anonymous Coward]

It doesn't have to be black or white. Just tending towards darker pages summed over all the users monitors could be worth while.

Re:Seriously?

[waives]

10% over thousands or millions of computers is a lot.

No it fucking isn't. This is the same bullshit bad math greenies are always spouting. "If everyone does a little, it adds up to a lot" Big savings require BIG changes on the part of each individual. If you save 4W displaying black screens on you LCD, even if you run it 24/7 for a year, you're only saving the equivalent of ONE FREAKING GALLON of gasoline.

Re:Seriously?

[zippthorne]

Not as dramatic as OLEDs promise, though, since you have to keep the steering magnetics going and the electron emitter hot whether you apply current to it or not. I'd bet that the steering magnets are the major power draw in a CRT anyway.

Re:Seriously?

[EvanED]

FWIW I see virtually no difference on my monitor (Dell U2210H). All-white screen at min brightness is 14W, all-black is 13W. At max brightness even that difference disappears; it's 33W for both. Unfortunately, my kill-a-watt only measures to 1 W granuality.

Re:Seriously?

[Anonymous Coward]

The biggest power consumer in a monitor is the backlight which is on all the time even in OLCD there's still power going though it. the major difference is how much does 1 color pixel take up you'll get less with black and more with white and some number in between with red ,blue or green.

Re:Seriously?

[Johnno74]

Parent is 100% correct. However I don't think you can get OLED monitors... yet. Quite a few cellphones use OLED screens though, such as my galaxy S.

OLED screens don't have a backlight at all. In an LCD screen the pixels are actually acting as filters, blocking part of the light from the backlight. In an OLED screen the pixels emit light themselves - black pixels are turned off and consume zero power.

For this reason turning the screen brightness down dramatically affects my battery life.

Re:Seriously?

[rev0lt]

You're not, because the energy you saved won't stop being produced anyway. You can pay less electricity (the right kind of savings), but the coal/CO2/whatever is bad nowadays analogy is always wrong. And, at least where I live, 20% of the electricity comes from certified renewable sources (and that's why it's so expensive).

Re:Seriously?

[isorox]

No, the big power draw is from CRT displays.
Both of them. They'll die someday and things will be nice and green again....

Back in my day the CRTs were green... or sometimes amber.

Or this one time, pepperoni! What a day!

Re:Seriously?

[Anonymous Coward]

How you do figure, where's your data? Their data clearly shows that a CRT displaying all white uses 85W, and the same monitor displaying all black uses 63W, which sounds to me like it's using 25% less power to display the black screen. For an LCD the difference is only about 10%. The grayscale comparisons clearly show a relationship between darkness and power draw.

This is ONLY true for CRT screens. Any form of LCD or LED screen has a constant backlight which is what draws the most power. OLED and Plasma are different and would both consume less power on a black screen.

Re:Seriously?

[rtb61]

So the next question is, can you use dark screen background in a dark room or is the contrast uncomfortable versus a white screen background. From personal experience a lighter background is far more usable in a darker room, the lights not turned on, this is really dependent on whether you have an illuminated keyboard or not.

So is an illuminated keyboard an energy waste or an energy saving? How much power does it use versus a light bulb?

Re:Seriously?

[Joce640k]

Maybe black on white just gives you such a huge afetrimage you don't regularly notice it?

Or maybe the type of afterimage is different and doesn't affect reading.

Whatever the reason, white on black=bad (and I'm sure I can't be the only one).

Old-school research showed white on dark blue was easiest on most people's eyes.

Maybe that was only true on CGA monitors...

Re:Seriously?

[Anonymous Coward]

I have a feeling everyone's ignoring the CRT part because, well, it's 2012.

Re:Seriously?

[ericloewe]

The actual electron gun doesn't really consume that much, but it does help a bit.

On OLED, power use is proportional to the brightness of the screen (more or less, and without processing)

Re:Seriously?

[Neil Boekend]

LED doesn't have a constant backlight. Real LED per definition, but those 3m (9 foot) displays are not what's meant here. LED backlit LCD (wich is faultily shortened to LED) has adifferent techniques. One of the techniques is called "Dynamic 'Local Dimming' LEDs". These use less power on a field of x by x pixels (for example 8 by 8) by lowering the power of the led behind that field if the lightest pixel of that field is darker.

Re:Seriously?

[Anonymous Coward]

"Use a larger, bolder font to avoid having ink spread obliterate fine serifs and thin strokes"
http://desktoppub.about.com/cs/intermediate/a/reversedtype.htm

"When reversed type gets printed, the ink has a tendency to spread into the type."
http://www.prepressure.com/design/basics/reversed_type

"Reversed type is generally hard to read in large amounts."
http://www.printindustry.com/Newsletters/Newsletter-126.aspx

possibly related: http://en.wikipedia.org/wiki/Filling-in

interesting: http://i-perception.perceptionweb.com/journal/I

Re:Seriously?

[burne]

The gun has a peak beam-current of 1 mA, in a 24" monitor, and that's at 28.5kV, so, 28.5W peak to start with. Add in another 6W for the kathode which is heated.

Assuming perfect electronics, which you don't have.

Driving the deflector-coils is something in the orde of 10-15W.

Re:Seriously?

[omglolbah]

But sadly it is minute compared to the draw of the machine you're running...

If I switched I'd save something like 12 watts (3 displays).

The computer, when running most of the time heats the whole apartment by 4-5C.

The displays are not the power-hogs here. While savings are good, perhaps it would be a good thing to focus on where the major power draw happens instead of the minor savings in the display.

Re:Seriously?

[qubezz]

In printing, black inks or toners tend to wick or spread into the white areas. On CRTs the effect is opposite, white tends to bleed into black areas (and be diffused by the shadow mask). We don't need to talk about either of these obsolete technologies, though.

Re:Seriously?

[gbjbaanb]

which was not invented to save power but to make dark areas of screen more black, as backlight bleeding from bright areas made dark scene look less murky than they should be.

TV review sites complained about this years ago, hence the on/off mechanism to try to make up for it. They just happen to save power too.

Re:Seriously?

[Anonymous Coward]

LCD != OLED, they're very different in their power draws

LCD has backlight running all the time, and pixels switch state from being opaque to transparent. The latter uses very little power, almost all the power is in the backlight which runs all the time regardless - so it makes sense LCD would have only a small difference.

OLED has no backlight. Individual pixels generate their own light, which means there's no backlight power draw but individual pixels use a lot more power. The image being shown has a MUCH greater impact on the power usage. If the screen were 100% black then every LED would be off and there would be no backlight running - in theory then the power usage would be nil (it won't be because the video controller's still running, but it'll be close).

Re:Seriously?

[ceoyoyo]

"...that actually indicates that there is at least a measurable difference."

No, it implies that there's a consistently measurable difference that meets accepted requirements for being statistically significant. I didn't see any error bars, never mind any p-values.

Re:Seriously?

[ceoyoyo]

That's not inconsistent. It's called error, or noise. Never trust a value with no error bars.

Re:Seriously?

[DarenN]

It was yellow on dark blue - which is why it was the default colour for those DOS prompts. It's not strictly "easier on the eye", but it's the best contrast you can get.

Re:Seriously?

[Anonymous Coward]

Other thing... white on black is hard on the eyes because of "black creep". If you're a typesetter, you know this - if you have light text on dark background, you have to increase the siez of the text in order to keep its apparent size the same. Also, thin fonts sink, so you may have to apply bolding to "fatten" them so they're still legible when the black background slims them down.

That's true on a printed surface (especially if you have ink that bleeds) but is the effect really equally severe in a backlit monitor (crt,lcd,led,oled)? I have personally always noticed printed white text on black brutal hard to read, but have always preferred reading white text on black on a screen. Especially at night I find it much much easier on the eyes. This is also why I always set my screen backgrounds to be black. So the only blazing white I have is from my open windows.

It may also contribute to why many old school programmers refuse to move to ide's. they know their code well enough that they just find they glaring white screen of the ide to be more hostile, enough so that it doesn't outweigh the benefits they'd otherwise get from autocompletion, and the other goodness and ide delivers etc...

Re:Seriously?

[Anonymous Coward]

The report is internally inconsistent.

• First they state figures for an all-white screen in their "Black and White" test: 85.1W (CRT), 38.4W (LCD).
• Then later they test an all-white screen in their "Greyscales" test: 84.9W (CRT), 40.0W (LCD).

So they show a 1.6 watt difference (LCD) on the same image, where their stated difference between google and blackie is 3.8 watts.

So they're still presenting their data when there are some inconsitent data points instead of trying to make their report perfect. This is call integrity. It's a good thing. If this was a shill do you think they'd allow any conflicting data through? Sure if they were smart, but how many smart shills have we seen? Not that many.

Re:Seriously?

[Anonymous Coward]

Seriously?
Did anyone here actually believe this? The big power draw is from the backlight, which is still running even with black pixels.

Yes, anyone here actually believed this. I guess in your hurry to post, you misread the double-negative in the summary...

I guess in your hurry to post, you assumed the gp read the summary....

Re:Seriously?

[biodata]

1W x a billion computers is quite significant though, given that our energy use is destroying the habitability of the planet.

Re:Seriously?

[Anonymous Coward]

It only assaults your eyes if you ambient light is too low.

Re:Seriously?

[fbjon]

As TFA shows, it's apparently not a myth at all, even for backlit screens.

Re:Seriously?

[fbjon]

Wouldn't a newer monitor with smarter backlight usage show a greater difference in power draw? It seems they've tested the worst case and still got a 10% difference.

Re:Seriously?

[Anonymous Coward]

With that information you can embark on your exploratory informational journey into discovering why not getting the same result every time still allows you to make accurate statements about the monitors' power usages. To start you off, google "statistics", "average", and "best fit".

Re:Seriously?

[dinfinity]

The problem is that the second page of the article is filled with almost 50 measurements that imply 'extensive testing' that add little, if anything, to the basic greyscale and color tests.

I can't help but feel that those tests were added simply to add more keywords ("social networks energy efficiency", jay!) to the article and to seemingly add more weight to their concluding "rules of thumb". In the mind of the general crowd it will stick as "They did a really big test and black websites cost less power than white websites because they use less light".
I'm under the impression that there is no lack of hollow easily misleading effect-chasing journalism. Assuming that's the case we shouldn't encourage more of it, regardless of potential positive effects that arise from it (which would be negligible, in this particular instance).

Re:Seriously?

[coachbolsas]

1, I decided to buy a car that the world with great snow, think of the bad weather, vendors must have thought that there will be no customers to come in, I am full of confidence ready to bargain vigorously. As I expected, when I entered the hall, I was the only customer. Vendor is an opening, I am ready to bargain fiercely hope that they immediately made void. He says proudly: "Young man, you definitely want to have the new car would like a very, very bad weather came out to buy a Bolsas Gucci." 2, the director of an actor angrily shout, "This is simply nonsense! That scene just before you die how can suddenly burst out laughing then?" The actors: "Relying on Bolsas Gucci to get you for giving me a monthly wage, my early demise relief." 3, a chef in a hotel for many years, has been holding a very low salary. Finally one day, the boss decided to give him a raise. "Why did you give me a raise?" Chef ask the boss. The boss said: "Because so many years you have been a good cook, so I should improve your treatment." Cook for a Bolsas Gucci, said: "So, you have to deceive me for many years."

Re:Seriously?

[Jerry Atrick]

On my SyncMaster 2343BW enabling Dynamic Contrast drives me crazy with the brightness changes and I've yet to see it improve an image in any way. On a windowed display it's got no chance of doing the right thing anyway. Does anyone actually leave this enabled?

Re:Seriously?

[dinfinity]

In relative power draw? Probably.
In absolute power draw? Perhaps.

But what effect does local dimming have?
Does it matter if you turn off dynamic contrast features?
I know I was hoping to see answers to these questions, preferably for newer monitors that assumingly employ modern technology. The current state of this bit of 'news' 'for nerds' is '8 year old stuff' 'that anybody with an interest in technology could have told you if they were twelve'.

Re:Seriously?

[CSMoran]

1W x a billion computers is quite significant though, given that our energy use is destroying the habitability of the planet.

Not really. That's just 1E+09 W compared to some 1.5E+13 W of energy that humanity uses today. So less than 0.01%, even if those PCs were on 24/7.

Re:Seriously?

[drinkypoo]

Bright stuff on a CRT display requires more power consumption because more electrons are fired at the screen. There is no additional penalty for animation vs. a static image of the same average brightness.

Animation makes LCD displays use more power because you have to change the state of the cells. It causes the display to warm up more.

Bright stuff on the screen makes LCD displays with dynamic contrast use more power because they produce more light from the backlight. Fluorescent backlighting runs across the screen in something like four or sixteen zones, depending on size, complexity, cost target, etc. These zones are turned up if any pixels anywhere within the zone need more brightness. So changing the background color will accomplish exactly nothing if there's any light text anywhere in the zone.

Bright stuff on the screen makes OLED displays emit more light which makes them consume more power. So more dark pixels will very likely save a significant portion of the display power consumption when using OLED.

Re:Seriously?

[swalve]

From what I know about LCD technology, the driver puts out variable power to each pixel in order to get it to a certain brightness level. Full power to make it completely opaque, zero power to make it completely transparent. So in theory, a completely white screen should use less power. However, I imagine that even a completely white screen is requiring the driver to put out some power to the pixels in order to maintain some kind of white balance. So the circuitry that varies the power level to the pixels must tend to be more inefficient when it is distributing the least power. Maybe it is a switching power supply that has to switch at a higher rate to "throttle" the power output.

Maybe they are designed that way on purpose to keep power draw more or less consistent? If this theory is right, then it goes basically like this: 1% power to pixels, 90% power to control circuitry, all the way up to 90% power to pixels, 10% power to control circuit, with the net varying between 91% and 100%. If they designed it the other way around, it would be 1% and 10%, all the way up to 90% and 10%, with a net power varying between 11% and 100%.

Re:Seriously?

[swalve]

1) Common sense says no, but the data says yes.

2) Are you sure about that? I get a terrible case of "white stripes" when reading white text on a dark background because of the memory effect of the eyes.

Re:Seriously?

[tompaulco]

Their data clearly shows that a CRT displaying all white uses 85W, and the same monitor displaying all black uses 63W, which sounds to me like it's using 25% less power to display the black screen. For an LCD the difference is only about 10%.
How much more does it cost to repair the headaches and/or damage to the eyes from reading white text on a black background?

Re:Seriously?

[swalve]

The takeaway is that if popular websites used darker backgrounds, the net power draw of all their users would go down. It wouldn't matter in the individual cases, but if the difference is 10w/hour, then over 1 million user-hours, a total of 10 megawatt-hours would be saved in the aggregate. If I've done my math right.

Re:Seriously?

[bill_mcgonigle]

If 'white' means you have to drive the LCD, then white takes more energy. If 'black' means you have to drive the LCD, then black takes more energy.

Exactly right. If anybody tries to patent this nonsense I can likely produce an e-mail exchange I had with the author of the BasicBlack screensaver for MacOS 7 in 1992, when I got a Powerbook 170 for school. That machine drove the "Active Matrix" LCD for black so he implemented a 'BasicWhite' mode.

Re:Seriously?

[Anonymous Coward]

Thanks from 1999!

Re:Seriously?

[amicusNYCL]

This is ONLY true for CRT screens.

So on this page (you know, the article), down in the table labeled "Greyscales and Computer monitor power consumption", where it clearly shows the LCD using 40W on a white screen and 35.5W on a black screen, you're saying that's not true, correct? Is their data wrong, is their LCD monitor faulty, or is everyone claiming that brightness has zero effect on an LCD power draw mistaken?

I'm having a real hard time figuring out why all these (smart?) people on Slashdot are claiming that brightness has no effect on power consumption in an LCD when we have hard data that very clearly and obviously shows that this is not the case. Are people just jumping in to comment on their profound knowledge of backlights without bothering to even glance at the data that they're commenting about? Don't get me wrong, a theoretical knowledge of how LCD monitors work is great, but we have an article here with very specific data which shows a very specific conclusion to a question that has been discussed about for a while. Why is everyone just ignoring the data now?

The question has been answered - yes, brightness has a fairly significant effect on CRTs, up to 25%. And yes, it also has an effect on LCDs, but only by about 10% (and the LCD is already using about half the power of the CRT anyway). So yeah, LCDs are more efficient than CRTs, and brightness does in fact effect power consumption in both CRT and LCD monitors. I don't see how anyone can come to any other conclusion.

Re:Seriously?

[AlienIntelligence]

How you do figure, where's your data? Their data clearly shows that a CRT displaying all white uses 85W, and the same monitor displaying all black uses 63W, which sounds to me like it's using 25% less power to display the black screen.

True. But really, who's using a CRT these days? Especially with a mobile device or some other method where you're using a battery instead of running off the mains? The fact that the power draw of a CRT changes with the image is technically true, but it's also practically irrelevant since CRT is a dead technology.

Up until last year, the cheap asses @ H&R Block were all tube monitors.

I tried to tell some higher ups, "how are we supposed to look like we know
what we are doing, if we have monitors that still take up 1/4 of our desk area?"

Like all greedy capitalistic US companies, this concept fell on deaf ears.
I show all my friends how easy it is to do taxes online, from the comfort
of their home. I don't think H&R is long for the world as its current incarnate.

-AI

Re:Seriously?

[AlienIntelligence]

So is an illuminated keyboard an energy waste or an energy saving? How much power does it use versus a light bulb?

Dude... you've got a 6 digit ID and you asked this question??

-AI

Re:Seriously?

[mcgrew]

CRT technology isn't dead until the last CRT goes into a landfill. Since CRTs last a LONG time, it will be a while before they're dead. Obsolete, yes, but not dead.

Like VCRs. Obsolete but still being used.

Re:Seriously?

[Anonymous Coward]

Wait. You're concerned with what a tax-preparer's desk will look like in relation to looking like they know what they're doing? I'd say sticking with CRTs until the need to be replaced is *exactly* the sort of sign that you'd be looking for. After all, they're not charging you so much of a premium that they can just go out and buy the latest and greatest whenever they want *and* they're not going to do something different just to look 'new'. Fiscal conservatism is *exactly* what you want to see from an accountant.

Re:Seriously?

[Anonymous Coward]

CRTs make sense, since they create light by firing electrons onto the back of the screen. More white requires more electrons. The majority of LCD screens' power is from the backlight, and it's always on. Color won't make a lot of difference there - I'd call it "negligible". LED type screens will draw some more for a brighter screen, simply because LED is a pretty much direct power-to-light conversion.
Where's my data? Simple logic. Do some research on how the technologies work and make your own conclusions. Don't trust someone just because they have numbers - how do you know those numbers are correct? Trust logic.

Re:Seriously?

[mattack2]

I tried to tell some higher ups, "how are we supposed to look like we know
what we are doing, if we have monitors that still take up 1/4 of our desk area?"

Maybe you look like you know what you're doing by NOT simply buying new monitors for no good reason? Like, saving your customers' money and thus charging less to do their taxes?

(I've done my own taxes online since at least the late 90s, so I'm definitely not promoting H&R Block.)

Re:Seriously?

[mattack2]

Of course it won't be produced, over the long run. If there is less demand, there will be less supply.

People stop buying gas, then eventually the oil production companies won't make it anymore.

Re:Seriously?

[Anonymous Coward]

How many CRT displays are there left?

Less and less every day I'd wager.....

Re:Seriously?

[rev0lt]

If people suddenly started consuming 10% less gas, probably most oil companies would keep the same production values as of today. Because 1) refined oil can be stored (unlike moving electrons) and 2) 10% is lower than the high-mark - low-mark consuming threshold 3) it would be cheaper to keep producing gas at current levels than having the refinery structure running at sub-optimal level.
Btw, a home vacuum cleaner consumption is about 300x the difference measured between a white page and a black page on an lcd. Don't even get me started on what _actually_ spends electricity (industrial machines).

Re:Seriously?

[Ol Olsoc]

I really don't know why you are so against this. Okay, maybe you prefer white on black... but you seem to hate it just because it's "green". If it makes you feel better it will reduce your electricity bills too.

I like green, I like saving money and energy. But I don't like silliness.

The idea of making everything black and white text because of some presumed energy saving is silly at best. So do we mandate html only, no pictures, or eliminating video? Trying to read that is very difficult, I get to one of these abominations, and I just move on. Especially the blue on back background. Just not ergonomic. There is a reason we don't use those old computer screens any more. They just are not as good.

If we really want to save some energy, unplug some wall warts. Turn your computer and screen off when it isn't in use. Turn the brightness down a bit. This business of nitpicking the design of webpages is a bad argument.

Re:Seriously?

[rtb61]

I will give you the benefit of the doubt and assume you fail to grasp common uses of English literature, unless of course you're being a cheeky sod and using en.wikipedia.org/wiki/Satire back against me.

I use the illuminated keyboard so I can 'dim' the lights watching a big screen TV whilst using that computer, reality quite a bit of power being used. I conserve elsewhere to make up for it, 'a small four cylinder car, who gives a crap about ego machines, the infernal combustion engine sucks'.

Re:Seriously?

[zymurgyboy]

Part of the appeal at the time blackle came out was that soooo many people had google set as the start/home page in their browser. That has to have gone down with the rise social media.

I fear for the future of my children. And my children's children.

It is a moral IMPERATIVE that someone develops a Blackfacebook.com NOW!

Won't someone think of the children, please?!?

Re:Seriously?

[toddestan]

And if the push is for darker web pages, the CRTs will last even longer as the phosphors will not wear out as fast :)

Re:Seriously?

[toddestan]

I find light text on a dark background much, much more readable in a dark room. A bright monitor in a dark room is uncomfortable, and I have to turn on a light or my eyes start to hurt after a while. Granted, I won't pick white on black, but more like a light pastel-like color on a darker background. Also I find just about every new LCD monitor uncomfortably bright at its default settings.

With that said, in a bright room light text on a dark background is also hard to read. At work where I don't have control over the lighting I use dark text on a light greyish background.

Re:Seriously?

[toddestan]

So is an illuminated keyboard an energy waste or an energy saving? How much power does it use versus a light bulb?

If the keyboard is powered from the USB port (all that I have seen are), the most it should be drawing is 2.5 W per the USB specification. Now granted, some hardware does play loose with that specification but it's not like illuminated keyboards are going to be pulling tens of watts like a light bulb.

Re:Seriously?

[AlienIntelligence]

I simply felt that geek cred, would have you knowing that answer.

A few different ways to devise a method to determine power consumption.
Digital voltmeter, Kill-A-Watt, count the LEDs and multiply by their wattage.

If you had a (ridiculous) number of 1W LEDs, let's say 14, then it would
be equiv to a standard "60W" CFL. Since you probably don't in that KB,
using the keyboard in lieu of additional illumination would net a savings.

Sorry, I just assume my geek brethern take in-depth interest into their
power usage. Maybe I'm the only kill-a-watt nerd here, but I know EXACTLY
how much juice every pluggable thing in my house uses.

And boy, after I built my last production workstation... WOW, it's power
usage gave me a heart attack. The Kill-A-Watt said $60/mo for elec, JUST
for that computer!

I seriously UNDERCLOCKED that bitch after that, just to get it to idle
@ 165-185W. Use the ASRock util, whenever I'm rendering or whathave.

-AI

Re:Seriously?

[AlienIntelligence]

Wait. You're concerned with what a tax-preparer's desk will look like in relation to looking like they know what they're doing? I'd say sticking with CRTs until the need to be replaced is *exactly* the sort of sign that you'd be looking for. After all, they're not charging you so much of a premium that they can just go out and buy the latest and greatest whenever they want *and* they're not going to do something different just to look 'new'. Fiscal conservatism is *exactly* what you want to see from an accountant.

Until you know how to do my job, don't question how
I'm doing it.

There is no easy way to fit two people that don't know
each other at a desk and share information on a monitor
that isn't easily pivotable left right.

The depth of the CRT's not only makes the swivel back
and forth to accommodate mom, dad and the young uns
into the process, a laborious task, as the connection points
are at the far end which interferes with the snug travel
down to the box snug so there aren't wires everywhere,
which was a corporate sent directive.

But it also limits the amount of room I have to store forms,
books and informational packets for my clients resulting in
my having to get up for a central area of forms, sometimes
waiting for others to get them, etc.

WASTING MY CLIENT'S TIME.

So, no... I don't want a "pretty new monitor" I want to work
at the efficiency level I know I can work at, when I have all
of my materials present.

Thanks for playing.

-AI

Re:Seriously?

[Anonymous Coward]

No, the big power draw is from CRT displays.
Both of them. They'll die someday and things will be nice and green again....

Back in my day the CRTs were green... or sometimes amber.

No, the big power draw is from CRT displays.
Both of them. They'll die someday and things will be nice and green again....

Back in my day the CRTs were green... or sometimes amber.

nice one

Re:Seriously?

[Lehk228]

it costs nothing to repair a headache, or $0.05 for an aspirin

no vision damage occurs from reading white on black, or from reading in dim light, or from reading small text. general eye strain / discomfort does not cause lasting vision impairment, although moderate vision impairment can lead directly to greater strain and discomfort and eyestrain can temporarily impact visual acuity

Watts aren't a unit of energy.

[Anonymous Coward]

The article is about the energy efficiency of various webpages. The only problem is that all the numbers are in Watts.

Re:Watts aren't a unit of energy.

[blueg3]

If you wait a few seconds, your watts will turn into joules.

Re:Watts aren't a unit of energy.

[Rhywden]

By that line of reasoning, Voltage is also a unit of energy.

Re:Watts aren't a unit of energy.

[Matt_Bennett]

Watt is a unit of power, energy is the integral of power over time. A common unit for energy is the Joule. Measuring power is a complex task (both the mathematical and figurative use of complex).

Re:Watts aren't a unit of energy.

[Xeranar]

Think of electricity as waves crashing against the beach. Amps are how tall they are, volts how many are arriving in a frame of time or frequency. Watts is a measurement that gives a volumetric answer to power usage. It's a perfectly valid way to measure since we pay based on wattage per hour.

Re:Watts aren't a unit of energy.

[capnchicken]

the difference is just 17.7W and 3.8W for CRT and LCD respectively. What that adds up to over the course of a year, for every second you spend doing a search on Google is anyone's guess.

That was my favorite part. I'm guessing they just hooked up a some kind of Kill-A-Watt given that:

PCSTATS has an electronic power meter which can actually measure the amount of energy it takes a monitor (LCD and CRT) to display any given website, we've actually got a valid set of criteria to look at.

Never mind the nomenclature, there is cost forecasting on those devices, and given a few basic parameters you could figure out the cost per year searching Blackle rather than Google on the back of a napkin, so its not "anyone's guess".

price_per_killowatt_hour: $0.10
hours_searching_google_per_day: 2 hrs
watts_saved: 17.7

hours_searching_google_per_year = hours_searching_google_per_day * 365
kilowatthours_saved_per_year = hours_searching_google_per_year * (watts_saved / 1000)
price_saved_per_year = kilowatthours_saved_per_year * price_per_killowatt_hour

Which comes out a little over a buck twenty five for a CRT and more than a quarter per year on an LCD using those parameters for one person.

Re:Watts aren't a unit of energy.

[Rotten]

if you cross the Atlantic, your Joules will turn into ergs

Re:Watts aren't a unit of energy.

[Anonymous Coward]

Voltage is a unit of energy (potential)...

Re:Watts aren't a unit of energy.

[ninjackn]

Watts is a unit of power. Multiplying voltage by current gives you power. Multiplying time by power gets you energy. More precisely integrating power over time gets you energy because power might not necessarily be constant over the duration of time.

It works for light bulbs because you assume a lot of things. If we were a more scientifically inclined society then light bulbs would be measured in Watt-hours and not watts. Light bulbs are mostly linear regarding their power usage which is why a 60 watt light bulb that runs for an hour uses less energy than a 120 watt light bulb ran for an hour.

Re:Watts aren't a unit of energy.

[geekoid]

times 300 million.

Re:Watts aren't a unit of energy.

[EmagGeek]

>> Voltage mutiplied by current in Amps equals Watts.

NO. For God's sake will people stop making this mistake.

Voltage multiplied by current in Amps equals VA, not Watts. If you want watts, you have to multiply Voltage in Volts, Current in Amps, and the cosine of the angle between them (which is more commonly known as the power factor.

VA = V*A
Watts = V*A*PF

Re:Watts aren't a unit of energy.

[JesseMcDonald]

Amps are how tall they are, volts how many are arriving in a frame of time or frequency.

Not that it affects the product (charge/energy), but amps measure transfer of charge over time, and volts measure electrical potential energy, so volts should be the height of the waves (gravitational potential energy) and amps the rate of arrival (in terms of volume of water per unit time, not waves per unit time).

It's a perfectly valid way to measure since we pay based on wattage per hour.

I don't know about where you're from, but around here we pay for energy in watt-hours (1 W*h = 3600 J), not watts per hour.

Re:Watts aren't a unit of energy.

[capnchicken]

I'm not saying whether it is a worthy consideration or not, I just had a problem with their "It's anyone's guess". All things being equal, you can certainly calculate it at scale too, but if you're in the "it's worthy thing to do" camp you also have to be honest about all things being equal (time spent reading web pages, time spent on computers making web pages conform to usability/marketing/business and energy guidelines, etc...).

Re:Watts aren't a unit of energy.

[gstrickler]

Of course, for the public, an even more common unit of energy is the kilowatt-hour (kWh). Scientists, and some engineers use Joules, but it's not common outside certain fields.

Re:Watts aren't a unit of energy.

[slinches]

I always thought ergs were a unit of frustration. For example, doing energy based calculations in Imperial/US customary units is a ton of ergs.

Re:Watts aren't a unit of energy.

[Anonymous Coward]

I always thought ergs were a unit of frustration.

My high school physics teacher explained to us that "erg" was the sound of a dyin' centimeter.

Re:Watts aren't a unit of energy.

[Tr3vin]

If anything they just reminded everyone that we should switch to LCDs if we haven't yet.

Re:Watts aren't a unit of energy.

[camperdave]

if you cross the Atlantic, your Joules will turn into ergs

And Verne, if you travel those 20,000 leagues under the sea...

Re:Watts aren't a unit of energy.

[theNetImp]

Funny I spent 4 years in a vocational highschool and this is what we were taught, guess my teacher who worked on apollo project is dumb eh?

Re:Watts aren't a unit of energy.

[Anonymous Coward]

U mad?

Captcha: ohmmeter. It's as though /. knows what we're talking about.

Re:Watts aren't a unit of energy.

[Sebastopol]

What about measuring power in a circuit? All of the design books I've read measure current in Amps then multiply by the suppy voltage. So that's VA, but it is a non-Ohmic circuit, so... is VA still the power requirement... I only ever see VA when talking about transmission line power. How should I measure / compute power of a circuit with a current meter and a volt meter?

Re:Watts aren't a unit of energy.

[willy_me]

>> Voltage mutiplied by current in Amps equals Watts.

NO. For God's sake will people stop making this mistake.

Voltage multiplied by current in Amps equals VA, not Watts. If you want watts, you have to multiply Voltage in Volts, Current in Amps, and the cosine of the angle between them (which is more commonly known as the power factor.

VA = V*A Watts = V*A*PF

No, Watts is really Voltage times Current. But when referring to AC systems, definitions get all screwed up. Just look at "kWh" - what a mess. It's like electricians have their own definitions for these units. I suppose it is understandable - using a single number to approximate a waveform and then performing calculations using Ohms Law makes most tasks much easier.

So pointing out the difference between Watts and VA is good - thanks for that. But don't be calling the real definition for Watts wrong. Also, your definition for power factor is not correct - or at least it is dated. It only applies to AC systems where the waveform is shifted. Power factor also applies to waveforms that are modified in other ways. For example, a computer power supply without power factor correction consumes pulses of power during the peak points of the sine wave. This changes the shape of the wave without resulting in a phase shift. With power factor correction, a control circuit draws power throughout the entire waveform so that the sine wave is not distorted.

I wonder what they used to measure power usage for this test. Did the instrument record true RMS power? Those instruments are much more expensive but required for accurate results. Guess I should rtfa.

Re:Watts aren't a unit of energy.

[Anonymous Coward]

Replying to myself here,

Looks like they used a Extech Power Analyzer - but they don't mention which model. But their current models all appear to utilize true RMS measurements.

Re:Watts aren't a unit of energy.

[Johnno74]

In high school I'm guessing you probably worked with DC current... where the current does NOT vary over time, so the power factor is 1

With AC power the parent is correct. However I think the power factor used by most devices is over .9,

Re:Watts aren't a unit of energy.

[Anonymous Coward]

You spend 2 hours searching google per day? Fuck! I know there may be some doing certain projects where this might happen, and I would not be terribly surprised if even I dwelled 2 hours for a day one time... but average?? no way.

Re:Watts aren't a unit of energy.

[umghhh]

the amount of energy consumed is dependent on many factors of which main two are nominal power consumption and time in which it happens. The power consumption of a light bulb is linear for all purposes relevant for its user. This may be different for appliances like dishwasher where indeed power consumption for standard usage (particular program, amount of dirt and fat it has to remove per load, detergents used etc).can be given and in fact is at least in Europe if you go to a shop that information is available. It may be not reliable and it certainly differs from what I and you would actually experience but that is good enough for comparisons. SO no scientifically oriented is good and I am with you on that one (at least as long as science is not fetishised) but light bulbs are marked in watts for a good reason.

Re:Watts aren't a unit of energy.

[rjstanford]

I wonder what they used to measure power usage for this test. Did the instrument record true RMS power? Those instruments are much more expensive but required for accurate results. Guess I should rtfa.

Well, if it did, then at least the power is free. Or wants to be. Or should be...

Re:Watts aren't a unit of energy.

[Anonymous Coward]

I don't know about where you're from, but around here we pay for energy in watt-hours (1 W*h = 3600 J), not watts per hour.

Hah! Around here, we pay for energy in kilowatt-hours (1 kWh = 3,600,000 J), not watt-hours. I guess you also have small dicks around where you're from?

Re:Watts aren't a unit of energy.

[ceoyoyo]

Guess what the power factor of DC is? Guess what that makes the equation?

Even when you are working with AC, it makes more sense to use the effective voltage and current.

Re:Watts aren't a unit of energy.

[ceoyoyo]

Except that to use Blackie I'd have to GO to Blackie and type in my query, whereas to use Google I can just type it into a search box without loading the page. I bet it takes more energy for Blackie to serve up the page, transfer it to me, and for my computer to display it than it saves because it's black.

Re:Watts aren't a unit of energy.

[tompaulco]

Which comes out a little over a buck twenty five for a CRT and more than a quarter per year on an LCD using those parameters for one person.
That is definitely not enough to overcome the cost of discomfort of trying to read the hideous light on dark at blackle.com.

Re:Watts aren't a unit of energy.

[Anonymous Coward]

It's a perfectly valid way to measure since we pay based on wattage per hour.

There's a wonderful bit of backward/circular reasoning. We measure it this way so it must be a good way to measure it.

We measure it that way because it's a good way, but that's not why we measure it that way. The why is because that's what represents how much energy was used.

Re:Watts aren't a unit of energy.

[willy_me]

Watts are calculated using Voltage and Amps therefore it is a unit of energy.

Watt is a unit for the rate of energy transfer. The actual unit for energy is the joule where "watts = joules / seconds". The term "kWh" is a term designed to allow people to easily determin home energy usage. It directly maps to joule with 1 kWh = 3.6e6 joules.

Blackle seems all well and good...

[dmacleod808]

Can I do an image search or a news search right from the home page? I am not sure if Google Custom Search supports these features beyond a simple web search.

Re:Blackle seems all well and good...

[Anonymous Coward]

Firefox + Stylish Add-on + Google Dark Theme (Web/Images)

Double Negative

[Anonymous Coward]

"turns out there is a not insignificant difference "

Double negatives are not not bad.

Re:Double Negative

[Anonymous Coward]

Double negatives are not not bad.

Yes they are.

Re:Double Negative

[Anonymous Coward]

To be fair, I think its just a way of avoiding saying its significant, AND insignificant at the same time. Thats not to say that I don't think that tactic has not previously gone unused by politicians and the like.

Re:Double Negative

[Anonymous Coward]

In this case, the double negative has a valid use. By saying "not insignificant" it leaves all other possibilities except for insignificant. This doesn't necessarily mean that the difference is significant, just that it isn't insignificant. If they said there is a "significant difference" then they have left only one option - that the difference is significant, and that statement carries more weight.

Re:Double Negative

[Anonymous Coward]

Nobody doesn't not like double negatives!

Re:Double Negative

[Trogre]

I couldn't possibly fail to disagree with you less.

Re:Double Negative

[b0nj0m0n]

I laughed, but this is probably one of the good ones. In the world of lay stats, "insignificant" means "throw away the results." If Timothy were to say "there was a significant difference" and it turned out to be "~12%" someone would object that 12% is actually quite low, and I would have to post that "he probably means statistical significance." One does not climb up from negative karma by merely laughing. But I did.

Re:Double Negative

[olau]

What you're basically saying is that it carries less information. When you write a summary, you generally want more information, not less. That is, unless you're writing it on Slashdot where it usually works the other way around. So I guess you could say it's a good Slashdot summary.

Re:Double Negative

[Sasha-Whitefur]

Except, "not insignificant", means there is significant difference. So that means it is true.

Re:Double Negative

[Anonymous Coward]

yes they aren't.

Re:Double Negative

[jonadab]

They may not be not bad, but it isn't necessarily true that they're nothing other than ungood, either.

Outdated...

[Anonymous Coward]

TFA is super old...live.com hasn't been a search engine since Bing was introduced in June 2009.

OLEDs and readability

[zaibazu]

I am interested in black background websites because they look prettier on OLED displays (Old Samsung Galaxy here as a reserve phone) . Readability should be driving the decision on the colours, not some % power saving.

So the answer is...

[fropenn]

buy an LCD (or LED) screen. That will save much more electricity than changing the colors you use on it. I can never figure out why so many energy saving tips focus on such small things (e.g., turn off the water when you brush your teeth) but ignore the big issues (like my neighbors who water all afternoon in 100 degree heat and have a stream of water running directly into the sewer).

Re:So the answer is...

[Eponymous Hero]

we get your point, but advice about not watering in the afternoon is almost always on the same list as turn off the water when you brush, along with sweep your driveway instead of hosing it down and wait til your dishwasher is full to run it.

Re:So the answer is...

[idontgno]

The time-honored metaphor for this is "carefully arranging the deck chairs on the Titanic as it sinks." We can fiddle trivial stuff and satisfy ourselves we're "DOING SOMETHING FOR <great cause>" while not actually changing the costly, momentous, or personally-significant things.

See also Matthew 7:3-5 if you're not opposed to Biblical proverbs.

Re:So the answer is...

[TheCarp]

Well if you already did that....

Frankly, I wonder why they didn't test the one thing I do as soon as I get a new LCD, which is actually recomended by several sites out there.... turn the brightness down to under 20%, sometimes, I go all the way to "0" (interesting that 0 brightness is not a black screen).

As an N=1 test, after realising that I couldn't easily tell the difference after a minute or two, was to take one of the most observant and territorial about her PC people I know, and changed the brightness all the way down while she was away.... just as I expected, she didn't even notice. I eventually told her she had been using the display with the brightness all the way down, she had no idea.

So I agree with all the people who say turn it down.... really, your brain will adjust the white levels on its own just fine.

Then... well... I like a black google...and any other site I can get. Not because of power savings but just because I always prefered dark backgrounds with light text on screens.

Re:So the answer is...

[omnichad]

This isn't true about going to zero, but having the brightness set above around 50% on new LCD's tend to blast out parts of the picture. And they come out of the box set too high. People just want to be dazzled by bright screens, nevermind the fact that they lost the difference between medium light grey and white with that setting.

See also: Store TV displays

Re:So the answer is...

[JonySuede]

See also Matthew 7:3-5 if you're not opposed to Biblical proverbs.

A good quote is a good quote, it whould be absurd for someone who claims to be a rational thinker, to be oppose to this quote on the basis that it came from a religious book.
That being said, as a non militant atheist( or agnostic I do not care about that disctinction), I find the first four books of the new testament agreeable if you remove the religious hockus pockus bullshit. However the rest of the bible is to my eyes an attrocity, and do not get me started on the koran or the "nothingness is nirvana, you must reincarnate until that" crap from most type of buddism.

Irrational beilief are, oh... well, irrational...

Re:So the answer is...

[Anonymous Coward]

Seems clear to me.

Let's take the nice case of the LCD (Note the CRT is more dramatic), and see what could happen if Google changed their page to a black background. With ~4W less power consumption per user, and assume at least a million users with the page open, that's 4MW. Now imagine the same for facebook.

It's like when you pay $1 of a $0.99 item and you don't want that cent. If 1million people do the same, you get $10k easily. It's aggregation, and given the energy consumption awareness and also that it won't save anything to Google or you, but overall consumes less resources, I say.. why not?

Re:So the answer is...

[TheCarp]

Yah I wasn't really serious about the 0 as black. Yah it does seem to help with that, for me its more about eye strain. When I turn down the brightness on an LCD low, I feel the difference in my eyes. Same for going to dark backgrounds, its less strain on my eyes. Not as much less as reading text on paper or e-ink, but it is very much noticeable to me.

I care about power usage, but only up to a point. In many ways, I am care more about not just wasting it. Keeping the lcd brightness higher than is needed, as you say, kills the real picture quality, so all that extra energy is actually worst than wasted...its actively making your experience worst.

Re:So the answer is...

[Anonymous Coward]

The idea is that morons wont do shit anyway and the people who care ALREADY use lcd monitors. so u have to teach them how to save even more.

Re:So the answer is...

[Anonymous Coward]

"like my neighbors who water all afternoon in 100 degree heat and have a stream of water running directly into the sewer"

Or my neighbors who *constantly* every-single-day have their heat pump/air conditioner going. Every day of the year. I've had my windows open since late February and do not expect to use AC until late June, or, if I'm lucky, July.

Likewise, no heat/AC usually from sometime in September until late Oct, possibly Nov (In SC).

Re:So the answer is...

[Green Salad]

Well...if 300 million people would stop brushing their teeth, that would "not be insignificant" towards creating offsets for your neighbor.

Really?

[Anonymous Coward]

Oh god. I was wondering why my screen randomly seems to increase/decrease in brightness.

I hate this feature. It makes me think someone slipped me some acid, and then I'm disappointed, because no, it's just bad attempts at saving power.

Re:Really?

[X0563511]

No, it's not. It's supposed to make the screen feel like it has a higher contrast ratio than it actually does.... and has nothing to do with power consumption.

Re:Really?

[DanTheStone]

.... and has nothing to do with power consumption.

Really? My external monitor at work defaulted to "Energy Smart Mode" (until I turned it off) which means "Dynamic dimming activated". I wouldn't say it has nothing to do with power consumption.

Re:Really?

[Pentium100]

It's a poor attempt at making the monitor have the same black levels as a CRT. Of course, a CRT would have the same black level whether the rest of the screen is white or black. It is not as good, but at least it is a step in the right direction. Ideally each pixel would have its own light source that is separately controlled.

Another way of achieving good contrast ratio is increasing the maximum brightness, after all, there is a large ratio between a 100W lightbulb and the sun...

Re:Really?

[X0563511]

I guess then it's intended to do what marketing says it is. I wonder what the actual intent was when the idea was brought to the table?

Re:Really?

[billcopc]

You should hate it. It's a shitty hack to make it look like your LCD has better contrast on paper.

I briefly owned a display like that. If I turned the dynamic contrast off, it looked washed out, and no amount of tweaking would get it looking even halfway decent. It was a shitty LCD but it was also 1/3rd the cost of my current photorealistic dazzlers.

It's the visual equivalent of the bass and treble boost knobs on cheap stereos.

Re:Really?

[uigrad_2000]

Well, he probably wasn't aware exactly which model of monitor you had. Generalizations tend to be bad for this reason.

I, for example, have an LCD projector with a dynamic iris. It dims the bulb for dark scenes, and it is only for the improvement in contrast ratios. I know this, because it doesn't dim the bulb by decreasing the voltage over the filament, but by closing shutters (the iris) between the bulb and the LCD panel. It's described in more detail here

I don't know the full history of the feature on monitors, but I'd assume it was originally to increase contrast ratio. After one marketer slapped a "energy efficient" sticker on the box, the manufacturers realized the marketing benefit of the feature, and probably renamed the menu for later models.

Re:Really?

[skids]

Different feature. Dynamic backlight power savings modes change based on the ambient illumination, because a monitor in an unlit room doesn't need to be as bright.

Dynamic Contrast dims the backlight when most of the screen is dark, to better comensate for how the human eye works with that sort of material.

Personally I'd just be happy if websites and applications were tested by their developers to work with dark themes and/or default browser colors, because I prefer light on dark text. Many websites hardcode their colors, which sucks, but what sucks even worse is when they do that and also miss hardcoding the background of HTML form input boxes. So the text is hardcoded black, and the broswer default colors for the background of the input boxes are black, and you cannot see what you are typing.

Re:Really?

[similar_name]

You seem to be suggesting that there can be only one reason for dynamic dimming.

Re:Really?

[Anonymous Coward]

Generalisations are *always* dangerous.

Re:Really?

[zippthorne]

Yeah, but you can dim the fluorescent lamp without changing the spectrum too much. WIth your projector, I'm guessing by your use of the word, "bulb," that you have a blackbody emitter as the light source. Reducing the power reduces the light output, but also changes the peak wavelength - http://en.wikipedia.org/wiki/Planck's_law. There are a few ways to handle this, but the iris is probably the most practical.

Re:Really?

[Anonymous Coward]

Don't most modern desktop operating systems use the concept of a desktop theme? Why could this theme not be extended to a website such as google?

Re:Really?

[Neil Boekend]

That's incorrect, although I suspect what you mean is correct. A flourescent light always gives off the same spectrum, dimmed or not. The spectrum of a fluorescent light is determined by the emission wavelengths of the phosphors (and the mercury). These don't change with power.
An incandescent light changes spectrum if you dimm it, because the temperature drops (see Black body radiation).
Since his example uses a fillament it has an incandescent light, and thus it would change.

Re:Really?

[drinkypoo]

My TV does this but I never notice. Next time get a better display :p

Re:Really?

[drinkypoo]

Since his example uses a fillament it has an incandescent light, and thus it would change.

It probably has an arc lamp, if it has any brightness worth mentioning.

Re:Really?

[dj245]

No, it's not. It's supposed to make the screen feel like it has a higher contrast ratio than it actually does..

That helps but it can't eliminate one problem. The human eye is lazy and is attracted to black. Black text on white is easy to read. White text on black is hard because your eye always wants to look at the black. There was a good example of this in a Calvin and Hobbes strip- the first 3 frames were daytime and the last was nighttime (black). It was hard to read the strip from the beginning because your eyes wanted to jump right to the last frame. I can't seem to find it however.

Re:Really?

[toddestan]

It's a lot less noticeable when watching TV. Try hooking a computer up and it'll look like shit. It's actually kind of amazing how really bad LCDs (judged by sending them test patterns via a PC) can still look acceptable for video.

Re:Really?

[drinkypoo]

It's a lot less noticeable when watching TV. Try hooking a computer up and it'll look like shit.

Maybe you should get a better television. Mine is a Sharp AQUOS set, and I'm on my second one. I used to have a 32" sitting on my desk with dynamic contrast turned on, never noticed it. Now we have a 52" in the living room, and the primary source is a PC running Windows XP, and I never notice it.

It's actually kind of amazing what pieces of shit people will buy.

OLED's

[imgod2u]

The idea is valid for all of the smartphones running OLED displays. OLED's take no power (or very little) to display a black pixel. It takes full power to display white.

Re:OLED's

[Anonymous Coward]

They do take more power to display some colors though. So it can even out in some ways as rarely is something all white or black.

Re:OLED's

[gl4ss]

I think lg made some pr stunt regarding this just in the couple of last weeks.

their claim was that an ips screen at 52% white(or more) was using less power than oled of the same size.

it's kind of bullshit, the nice thing about oled screens on mobiles is that you can display clock faintly when the device is locked/sleeping.

but using black pages to save the earth? wtf...

Re:OLED's

[gbjbaanb]

well, every little helps. It may only be a watt or so, but when you have 2 billion people using them, that's 2 billion watts!

AMOLED?

[RedACE7500]

Power is more of a concern on mobile devices and mostly dark/black displays will allow AMOLEDs to turn off some pixels to save power and extend battery life.

Re:AMOLED?

[JStyle]

You are correct. Here's some hard data: http://data.4dsystems.com.au/downloads/micro-OLED/Docs/4D_AMOLED_Presentation.pdf

This is why I use a black background on my phone.

Off the top of my head...

[Anonymous Coward]

seems like a funny question, but my guess would be dependent on screen time:

A) CRT - white requires more than black (black pixels have no electron hitting them)

B) LCD - black requires more than white (black pixels require a stimulated liquid crystal to darken and block the backlight)

C) OLED - white requires more than black (black pixels are actually "off")

D) LED backlit LCD - white requires more than black (white pixels require corresponding backlight LED to illuminate)

And in all cases, with the possible exception of LED backlit, I'm going to guess that this accounts for little-to-no effect on the overall draw of the monitor.

Oh comeon...

[Anonymous Coward]

turns out there is a not insignificant difference ...

Did some one seriously write this? Or did slashdot's queue automatically translate it from English to stupid? Why even employ editors?

Re:Oh comeon...

[garrettg84]

AC speaks the truth. I had to read the last line again to make sure I had the proper negations in place.

Re:Oh comeon...

[ArundelCastle]

turns out there is a not insignificant difference ...

Did some one seriously write this? Or did slashdot's queue automatically translate it from English to stupid?

That's fair. The more appropriate Slashdottism would be "non-zero".

Re:Oh comeon...

[Cyko_01]

I think that was what they intended to say. They are implying that it is midly significant without going so far as to say it is significant. It is awkwardly written but it is by no means ungrammatical.

interpretation? only 17 w

[Anonymous Coward]

Sigh, find authors' schools, request revokation of diplomas. They say "only 17W" difference for the CRT -- that's 17 out of 85! which is 20%-- that's enormous when integrated over a large number of displays. The LCD difference is smaller but still potentially signficant. That being said, there are probably better places to hunt down 17W savings.

I should have submitted this too...

[dyingtolive]

Except I would have said

"Are not dark webdesigns an energy unsaving alternative to a snow white Google? The theory is that websites with black backgrounds don't save energy, based not on the assumption that a monitor requires more power to display a white screen than black. Is not this not a earnest endeavor by Blackle.com, or a not earnest not green not washing not not not not not ploy by not Blackle.com? To find out, PCSTATS didnt't not hook up an Extech Power Analyzer to a 19" CRT and a 19" LCD and measured power draw — turns out there is a significant difference ..."

Mine would have been shot down for being too readable though.

Re:I should have submitted this too...

[Anonymous Coward]

Funny, but why is everyone picking on the AC for using a double negative instead of for using it poorly? Perhaps "non-insignificant" would have been more fluid, but double negatives are not incorrect. That's right, I mean "not incorrect", which isn't exactly the same as "correct". Just as "not insignificant" isn't exactly the same as "significant". It's called a litote, and is a part of English rhetoric.

Re:I should have submitted this too...

[Anonymous Coward]

lol I was about to respond that your paragraph is not readable either. I was going to suggest that you read it out loud as a way to figure out what you should improve.

Then I read it outloud, realized how bad it actually was, and that you clearly did it on purpose. Woosh moment averted.

Re:No shit...

[Jeremiah Cornelius]

There is a not insignificant parsing complexity.

Printer Ink

[Anonymous Coward]

Think of all the wasted energy from the fact that everytime you print, you will need an entire printer cartridge!

Re:Printer Ink

[skids]

Who prints anymore? The only printers I own are in the process of being hacked for robotics.

Re:Printer Ink

[Green Salad]

I laser-print my spam to save all that power consumed by viewing it on my monitor.

Re:No shit...

[busyqth]

This.

It is obvious that black is good for the earth and white is bad.
Why do you think we have climate change? Because of white, of course. No one has even heard of climate change before white messed everything up.

Not only is white bad, white is unhip. What do you want at your disco? White lights? No, black lights produce the right mood.

Let's fight the white and save the world!

drive 1% less

[Anonymous Coward]

try driving 1% less that will make more difference.

infact drive 20% less. then you might make a useful difference. also have a look at this (free) book http://www.withouthotair.com/Contents.html . it has a good explanation as to why the 'every little helps' motto is nonsence.

Only Applies to OLEDS; Reduces Readability

[Anonymous Coward]

First, as other commenters have already pointed out, this only applies to OLED and CRT monitors. Secondly, I would much prefer to have readable text than to save 5 minutes of battery, or to prevent half a gram of CO2 emissions.

No one ever said it did

[auntieNeo]

Even when Google first did this, they had a disclaimer that said that black web pages don't really save power. It's just an awareness campaign. This is not news.

Real and myth...

[jedirock]

It's real for CRTs (why do we still test these anyways?) and OLED screens. It's a myth for LCDs, including those "LED" screens everyone's touting nowadays. CRTs and OLEDs do take more power to display a white pixel because of the way they work. LCDs depend on the backlight to produce a visible image, and the backlight is always on. The only use case where the LCD had lower consumption was a totally black screen and with HardOCP: dark enough to trigger the darkening of the backlight in "dynamic" contrast (which is a farce anyways). Turn off dynamic contrast, and suddenly there will be no power savings. This isn't a story...

Re:Real and myth...

[Anonymous Coward]

It's a myth for LCDs, including those "LED" screens everyone's touting nowadays

They tested it, they showed a difference. As far as I care, it does make a difference unless another test shows something different. In that case, we need more tests.

Re:Real and myth...

[EvanED]

FWIW I hooked up my kill-a-watt to my newer monitor (Dell 2312HM; my older one is almost the same build so I was too lazy to test it). At minimum brightness I got 13W with pure black and 14W with pure white. At maximum brightness I got 33W with both.

It's not the most precise tool, but there's another data point for you. :-) (One perhaps-relevant thing: I'm 99% positive dynamic contrast is off.)

CRTs?

[Anonymous Coward]

People still have CRTs?

How ridiculous.

The reason the CRT draws more power on a white screen is because to get a dark screen, it has a little control grid (well, actually, in a CRT it's more like a little bass drum with a pinhole in it).

With the control grid negative about 20 volts, that stops the flow of electrons to the currently addressed point on the screen. No current means no power wasted.

On the other hand, most flat-screen displays have a backlight that's always 100% on all the time, and the LCD pixels block the light as needed. The LCD pixels are flipped on and off by a very small control current, much less than the backlight current, so a LCD is going to show very small differences between a black and a white screen.

So the reasons for the results are obvious.

A better question is, should we care? The difference is only a few watts, even for a CRT. And if you want to make the difference even smaller, just turn down the CRT brightness. Or if the CRT is getting old, as most of them are, it might make energy sense to toss away the CRT and get a more efficient display.

Re:CRTs?

[Brian Feldman]

CRTs per se may not be useful much anymore but plasma certainly is!

Re:CRTs?

[Pentium100]

People still have CRTs?
How ridiculous.

Ability to display perfect black color;
Ability to display more than one resolution correctly (useful for games, old video card = new games at reduced resolution);
Ultrafast response time, no input lag;
Reliable and have long life (people saying things like "My LCD started acting weird, but it's 3 years old, time for a new one", while my 12 year old CRT works great), but can also be repaired if necessary (well, other than the failure of the tube obviously);
More affordable than a 24" LCD that can display 2304x1440 (if such a thing even exists);
Great image quality.

The only advantages of LCDs are size, weight and power consumption - all of these are not primary features of a monitor, at least for me (the same way that I don't buy a car based solely on the fuel consumption, or a computer based on its power consumption and size - I look for performance and cost first).

Re:CRTs?

[Thing 1]

The only advantages of LCDs are size, weight and power consumption - all of these are not primary features of a monitor, at least for me (the same way that I don't buy a car based solely on the fuel consumption, or a computer based on its power consumption and size - I look for performance and cost first).

The LCD advantage that I prefer? Not irradiating remaining eye.

Re:CRTs?

[cyachallenge]

My main frustration with CRTs are the lack of current manufacturers. If you want a CRT that has good refresh rate, good resolution, and good contrast you're somewhat out of luck. You're talking about a peice of hardware that's now reserved for a niche economy where demand is low and prices are high.

Re:CRTs?

[Pentium100]

Completely agree. At least there are some nice used ones - I recently bought a Sony GDM-FW900, while it has some scratches on the plastic case, the screen is unscratched and the tube seems not worn (as the monitor is not too bright - my other monitor (Dell P1130) was way too bright, I had to use special software to reduce the G2 voltage, the monitor is still too bright ~15 minutes after turning on until the tube warms up; now that I replaced it I'll be able to properly configure it, hopefully, the "too bright while cold" problem is a compensation circuit going out of alignment with the tube (cold tube is darker, so the circuit increases the brightness, but in my case it overdoes it).

Re:CRTs?

[Anonymous Coward]

Ability to display perfect black color;

Quit buying cheap crap.

Ability to display more than one resolution correctly (useful for games, old video card = new games at reduced resolution);

Who cares.

Ultrafast response time, no input lag;

Yeah I bet you can tell the difference. Don't give me some bullshit story about you have faster reflexes then every other noob, you are full of shit.

Reliable and have long life (people saying things like "My LCD started acting weird, but it's 3 years old, time for a new one", while my 12 year old CRT works great), but can also be repaired if necessary (well, other than the failure of the tube obviously);

Yay for confirmation bias!

More affordable than a 24" LCD that can display 2304x1440 (if such a thing even exists);

WTF no. Enjoy your bizarro land resolution that no one targets.

Great image quality.

I bet you listen to vinyl records too. Fucking hipsters.

The only advantages of LCDs are size, weight and power consumption - all of these are not primary features of a monitor, at least for me (the same way that I don't buy a car based solely on the fuel consumption, or a computer based on its power consumption and size - I look for performance and cost first).

Try not straining your eyes to the point of ruining them.

Re:CRTs?

[manoweb]

CRTs have big geometry problems, uneven quality of the pixels (the ones in the corners will always be of a lesser quality) that a flat matrix panel simply does not have by definition. CRTs also take up so much space that is ridiculous.

Re:CRTs?

[Pentium100]

Who cares.

I do, I have more than one PC and some of them cannot output 1920x1200 or 2304x1440, non-native resolutions look awful on fixed pixel displays. As for games, yea, I do not want to buy a really expensive video card and then replace it every year or so just so that I could play new games at the native resolution.

WTF no. Enjoy your bizarro land resolution that no one targets.

2304x1440 is a normal 16:10 resolution (2304/16 = 1440/10). It also results in larger desktop space than 1920x1200. The good thing about CRTs is that I can use 1920x1200 for, say, watching movies and then switch to 2304x1440 if I need more space on the desktop because of all the windows etc.

I bet you listen to vinyl records too. Fucking hipsters.

Vinyl, shellac, tape, basically any form of media - why should I restrict myself to one or two formats? I like older music, I can usually find cheap records that contain the music I like, why should I not buy them? In some cases there is no digital equivalent available - if there are CDs released that contain the songs, they are usually remade or at least remastered to make them sound more "modern", but I prefer the original.

Re:CRTs?

[Anonymous Coward]

Ability to display perfect black color;

How about NO, Scott?

I've never seen a CRT that didn't have at least some kind of luminance above 0 when displaying all black. By contrast, I have seen many OLED displays that do. Your move, hot-shot.

Re:CRTs?

[Pentium100]

CRTs also take up so much space that is ridiculous.

Yea, because I always thought "If only my monitor didn''t take up so much space, I could put so many things behind it" :).

CRTs have big geometry problems, uneven quality of the pixels (the ones in the corners will always be of a lesser quality) that a flat matrix panel simply does not have by definition.

My current monitor does not have geometry problems (noticeable, anyway, I did not use a ruler to see if the lines are straight). It is possible to fix the geometry issues by using WinDAS - it divides the screen into small sections and you adjust the geometry/convergence in each of them (unlike using the on-screen menu that only allows changes over the entire screen).

Re:CRTs?

[Pentium100]

When my monitor displays "black" it looks like it is turned off.

Re:CRTs?

[Anonymous Coward]

And a more stable image to boot. I used to have a top of the line CRT display, but recently switched to the cheapest LCD I could find (it's a Philips if you must know). I immediately noticed that my eyes don't get tired any more. And the image looks better as well, due to subpixel rendering of fonts, and I've had to adjust the gamma only once: when I bought it.
And yes, my CRT had darker black. Not a big advandage in practice, and it certainly doesn't make the downsides of a CRT tolerable.

Re:CRTs?

[EvanED]

Yea, because I always thought "If only my monitor didn''t take up so much space, I could put so many things behind it" :).

As a counter argument, if everyone in my office had CRTs the same size of our LCDs, we'd have to significantly rearrange the office; at home, my current desk just flat out wouldn't work. In both cases it's because the monitors are far back. In the office the extra depth would mean that, to maintain a comfortable distance from the screens and still have the keyboard at a good location, we'd have to move the desks away from the wall -- but I'm sitting almost back-to-back with someone, and the office is too narrow for us to both do that. (A keyboard tray would leave the same fundamental problem, though eliminating the desk-moving necessity. Though that would also mean that... I wouldn't really have a desk after that.) At home, I built my own standing desk. Due to... I guess not good enough planning (I did anticipate this issue a little bit but not nearly to the degree that it happened), the desk is a bit wobbly and back-heavy. (It will stand upright, but I don't think it'd take much of a bump for stuff -- read: monitors -- to slide off the back.) Right now I have a piece of wood between the desk and the wall that will keep it from tipping over backwards; if I moved it away from the wall to make room for the extra CRT depth, I'd have to come up with some other means to keep it stable. In either case, moving it away from the wall

In other words: I haven't thought "I'm glad I can put lots behind it", but I definitely rely on pushing the monitors back.

Re:CRTs?

[Anonymous Coward]

Ability to display perfect black color

meh, they tend to have large gamma. If you want to make them more linear at the bottom end you have to turn the brightness up, no more perfect black. LCD's probably get blacker while still providing shadow detail.

Ability to display more than one resolution correctly

"more than one refresh rate correctly" might be more interesting. It seems like there should be an impact for video, that you'd want 60Hz for NTSC, 75Hz for PAL, 72Hz for film, and that not having this would mean stuttering or tearing. The same problem seems like it would apply to projectors, which definitely don't change the speed of the colorwheel depending on content. In practice everything seems to "just work", and I notice no artifact, so not sure what's the whole story here.

my 12 year old CRT works great), but can also be repaired if necessary

I've tried to repair CRT's and usually failed. It's more like, "sometimes you get lucky and can find some sketchball shop that happens to repair it. hopefully it doesn't start silently leaking xrays because of miscalibration." I've tried both mom-and-pop shops and the factory. sorry, just can't agree they can be repaired in practice.

The only advantages of LCDs are

The biggest advantage is probably that LCD's are significantly brighter. Also I think they probably need less warm-up time and/or calibration, which means you don't have to trade off power waste for color stability.

but a lot of people think LCD's look better or are "sharper". Try an old Nanao tube and tell me if you still think that! The good CRT's were very good.

Re:CRTs?

[Pentium100]

I put my monitor in the corner and move the desk away from the corner of my room by a few cm. Pushing the monitor even more back would require me to lower the resolution, so a thinner monitor would mean unused space behind it). Also, my desk has a keyboard tray. The desk is also strong enough to not only support the 42kg monitor, but also a 25kg tape deck. As the desk was bought a long time ago (when LCDs were only used in laptops), putting the monitor in the corner was a good idea, and still is now (since I still use a CRT, not the same one though). If your monitor is flat against a wall then you will have problems with the size of a CRT, byt then again, the desk was designed with a LCD in mind.

Re:CRTs?

[camperdave]

CRTs have big geometry problems...
CRTs also take up so much space that is ridiculous.

Is that not also a geometry problem?

Re:CRTs?

[EvanED]

The biggest advantage is probably that LCD's are significantly brighter.

Actually it's funny... if I were to name my single biggest gripe with my LCDs (Dell Ultrasharp IPSs), it would by without a doubt be that even at their dimmest, they are still too bright for dark environments. For instance, I occasionally have trouble falling asleep and decide to get up and do something for 30 minutes or an hour or something before going back to bed. And even though my monitors are at their dimmest settings virtually all the time, they're still painfully bright. Doing a quick Google search there are actually a couple programs (e.g. this) that I'll have to try out that may help a bit.

Re:CRTs?

[Pentium100]

meh, they tend to have large gamma. If you want to make them more linear at the bottom end you have to turn the brightness up, no more perfect black.

This is why there is software that lets you adjust gamma. Even some games allow it, but it can also be done with the video drivers (at least ATI/AMD ones, there are separate adjustments for desktop and full screen 3D).

It seems like there should be an impact for video, that you'd want 60Hz for NTSC, 75Hz for PAL, 72Hz for film, and that not having this would mean stuttering or tearing.

I would rather have 120Hz for NTSC, 100Hz for PAL and 96Hz for film. My monitor could support that for SD resolutions, but I do not know about 1080p, it is not written in the manual and I do not know how to calculate it based on the horizontal frequency (which goes up to 121kHz). However, like you, I have not noticed tearing. I do notice LCD scaling artifacts though.

I've tried to repair CRT's and usually failed.

Depends on what has failed. I repaired a CRT TV that would no longer display anything. It turns out that the horizontal deflection transistor failed for some reason. I put a new one in and the 18 year old TV works fine.
If the tube fails then it's over, but if the problem is with the electronics then it can be found and fixed.

The biggest advantage is probably that LCD's are significantly brighter

Depends on the user. I agree that bright displays are good for laptops so that I can still see the image even though it's sunny and I am wearing sunglasses. However, for my room, I don't need a bright monitor as I don't wear sunglasses and the lighting is a single 40W lightbulb. It also means that I notice the not-so-black blacks more easily.

The biggest advantage is probably that LCD's are significantly brighter.

And also very well designed/built. For example, using special software it is possible to adjust convergence in 64 (IIRC) separate sectors. Also, all the wires inside are thick, so there are no worries about breaking some really thin wire when taking the monitor apart (the high voltage is another matter though).

Re:CRTs?

[EvanED]

Doing a quick Google search there are actually a couple programs (e.g. this) that I'll have to try out that may help a bit.

So that seems to have roughly the same effect as lowering contrast. It's a bit nicer in some ways (faster control) but doesn't go all that far toward the solution. Oh well.

Re:CRTs?

[hokeyru]

They throw off less heat, too.

Re:CRTs?

[bdabautcb]

Nice post! I am running a ten year old Dell on XP with a 15 year RT monitor (I broke the nice 21 inch or whatever they were selling in 2002, and replaced it with a 'throwaway' 17 inch CRT from a friends business). The only thing I have replaced in the machine is the video card, and it is still going strong. I admit that the last high end game I bought was HL2, but it plays nicely. I am not a person that buys into the 'three year old hardware is obsolete' crowd, but the 'planned failure' model pisses me off. I am writing this post from a 2009 netbook my brother bought, HD failed, so I installed Ubuntu linux from live boot to a USB external HD. Works fine.

Re:CRTs?

[Pentium100]

This is because the cold cathode lamp cannot output any light level from zero to its maximum, the way an incandescent lightbulb, or an LED can. CRTs also can, because the amount of light depends on the current which can be varied from zero to some maximum.

Re:CRTs?

[CBravo]

The only thing I've seen failing on an LCD is the power button. Second, it is much less strain on my eyes, directly measurable in hours / day.

Re:CRTs?

[Pentium100]

I have seen failed caps, dead pixels and a dead driver chip (which results in an entire bar of dead pixels).

As for strain, I can look at my CRT monitor (runing at 85Hz) for over 12 hours/day, so I don't think it's that big a deal, unless you are comparing an LCD with a crap CRT (that only runs at 60Hz).

Re:CRTs?

[jones_supa]

Ability to display perfect black color;

If you look at a turned off CRT, you can see that the phosphor material is not completely black, it's always a bit grey. This would suggest that by using a very good TFT monitor, you could get even better black level.

Re:CRTs?

[Pentium100]

Or, if I want to play Doom3 or some other very dark game, I can just turn off the light in the room, then the only light source will be the monitor (and some LEDs on the PC) and the color of the phosphor will not matter.

Re:CRTs?

[CBravo]

I'll give you dead pixels, on CRT as wel btw. As for the strain: I can watch 12 hrs with LCD and about 8 with CRT (Iiyama vision master 510, 85 Hz). It may be dust related (dust parts on the monitor get propelled at anything in front of them because of the static charge).

Re:CRTs?

[Pentium100]

Usually static charge attracts dust instead of pushing it away, the flyback transformer and EHT wire inside a monitor are usually covered with a layer of dust.
Maybe my monitor is better or whatever, but I have no problems with eye strain watching it. Then again, I have set the contrast/brightness to a low level and the the light in my room is not intense either, maybe that's why. If I look at a laptop screen at full brightness for long I can get a headache, but if I turn it down (in my room that means down to the minimal setting) it's OK.

Re:CRTs?

[jones_supa]

That's correct, sir.

Re:CRTs?

[GuB-42]

I use a 12 year old CRT that was considered relatively high quality at the time (Iiyama Vision Master Pro 510). So let me answer your claims.
- Ability to display perfect black color :
When the brightness is not set too high the blacks are great (better than LCD) but not perfect. When the brightness it at 100% it is worse than the cheapest LCDs.
- Ability to display more than one resolution correctly :
True, great for games, especially considering that reducing the resolution increases the refresh rate (to about 150Hz)
- Ultrafast response time, no input lag :
True, I especially like the high refresh rate. As for the input lag, my skills are far too low to take advantage of this.
- Reliable and have long life :
Yes and no : Yes because my monitor is 12 years old and just refuses to die and no because there is significant degradation in the colors. I lost about 20% contrast in red and blue leading to a greenish tint in dark areas that is difficult to correct.
- More affordable than a 24" LCD that can display 2304x1440 :
It is difficult to compare prices because CRTs are now a rarity but I remember paying close to $1000 for mine. So let's say it is in the same category as current 2560x1440 LCDs. But I with a maximum resolution of 2048x1536, I stayed well above LCDs for a long time.
- Great image quality :
It is subjective. I find LCDs better for text and CRTs better for moving pictures. At high resolution / high refresh rate, my CRT becomes blurry.

Re:CRTs?

[Pentium100]

When the brightness is not set too high the blacks are great (better than LCD) but not perfect. When the brightness it at 100% it is worse than the cheapest LCDs.

Yes, because "brightness" for a CRT means "black level" or "offset" - the setting basically makes blacks not that black. If you want white color to be brighter, you should increase "contrast" which means "gain".

True, I especially like the high refresh rate. As for the input lag, my skills are far too low to take advantage of this.

Input lag for me isn't so much about skills as it can make the image "feel wrong" if it is excessive. And LCDs increase input lag to achieve fast response, I guess more processing is needed if you want the pixel to change the state faster.

I lost about 20% contrast in red and blue leading to a greenish tint in dark areas that is difficult to correct.

My Dell P1130 also has this problem. However, it can be corrected in one of two ways. I managed to approximate it in the advanced color settings, where I could adjust the offset and gain for each color. A better way to do it is using the WinDAS software (connecting monitor to a RS232 port) to adjust it properly, but that requires a colorimeter, the software basically says "show full screen white, adjust these sliders so that colorimeter showx x: ... y: ...". That software works for Sony Trinitron monitors, maybe there is software that works with yours. Also, at least AMD video card drivers allow me to set the offset, gain and gamma for each color.

At high resolution / high refresh rate, my CRT becomes blurry.

Get a better cable. 1920x1200@85Hz is about 300MHz pixel clock, the cable has to be really good to pass it without blur (limited bandwidth) or ghosting (reflections because of impedance mismatch somewhere).
Also, I bought Nvidia GTX 260 video card and it made the monitor blurry at high resolutions - most likely the analog circuitry was poorly designed or too cheap to cope with the high frequencies. I returned the card and continued to use AMD HD2900XT, later replaced it with a 6850 and the analog output is still good.

Re:God is my salvation.

[gmuslera]

That is ontopic. You try to read that page, then turn off the computer and leave internet for a few days. That is really power saving

Webpage almost crashed IE8

[cpu6502]

Maybe PCstats should apply their own power-saving strategies to themselves (less CPU-intensive flash crap).

Anyway it appears only the CRT has a significant savings with White google versus Black blackle.com. LCDs gain almost nothing.

Re:Webpage almost crashed IE8

[Anonymous Coward]

Maybe you shouldn't use IE or flash...

Also, multiply "almost nothing" by 1 billion for google alone...

For one person, no - but...

[bigattichouse]

I'm not really double checking my #'s here....

1 billion queries per day in 2011 (quick online search)... lets say that 1 user makes 100 queries/day (so 10 million users) and each query takes about 10 seconds to complete. 100 million seconds burning 4 watts yields 400 megawatts per day. If we average that out per hour, then we're burning 16 megawatts per hour 24/7. Each day, enough to power 8-16 households (1000-2000kwh) for a month... so over a month: 240-480 households with pretty wasteful practices.

SO, yes, 4 Watts isn't much to an individual household - but aggregated, 4 watts is a lot.

Re:For one person, no - but...

[MozeeToby]

Could you explain what megawatts per day means?

Re:For one person, no - but...

[bigattichouse]

a single day of queries (1 billion), ended up (in my calculation) resulting in using 400 megawatts. so, 400 megawatts being used per day.

Re:For one person, no - but...

[omnichad]

Try using standard units like Megawatt hours. Your example gives a saving of 0.11 Megawatt Hours (mWh) or 111 kWh. Then, you compared to actual kWh assuming it was interchangeable with what's essentially megawatt-seconds.

Re:For one person, no - but...

[isorox]

Could you explain what megawatts per day means?

It's a measurement of increasing power, as in "my house is drawing 5MW increasing at 2MW per day. By next year I'll have melted the planet!"

Re:For one person, no - but...

[Anonymous Coward]

Learn physics you moron. Watt per day is nonsense.

I'm finally green!!!!

[crazyjj]

Yay! My Black Sabbath fan site is one of the most environmentally-friendly sites on the internet!!

So do I win some kind of a prize?

[KlomDark]

I've been running MessageBase with a black background because of this exact reason since the late 1990s. Everyone told me it was a stupid idea and the power savings were negligable.

Think of all the power I've saved people! I've done my part.

Re:So do I win some kind of a prize?

[Anonymous Coward]

Think how much more power you would save people by shutting the site down!

Re:So do I win some kind of a prize?

[Hatta]

It's not just good for power. It's hard to stare at a white backlit source for a long time. Muted colors on a black background are the easiest on the eyes.

Re:So do I win some kind of a prize?

[KlomDark]

Very true, very true. Damn thing never caught on...

Why is the question? Was it the black background?

Re:So do I win some kind of a prize?

[camperdave]

My site is a lot better, since nobody even goes there.

The headline..

[Tuan121]

turns out there is a not insignificant difference ...

Very clear...

Re:The headline..

[Surt]

Curse of the double negative strikes again.

Their own number don't even agree...

[fahrbot-bot]

In the "Black & White" table they list white at 38.4 W, then in the "Greyscales" table list 0% grey (white) at 40.0W and 60% grey at 38.5W -- all for the same 19" LCD Samsung 192MP monitor showing a full-screen solid color. For fluorescent back-lights, I can't imagine the power usage to be that different for just toggling the LCD cells, but can for an LED back-light, where there are grids of LEDs that may be powered down/off for a more true "black".

Re:Their own number don't even agree...

[bussdriver]

Web pages with FLASH waste more power.

Grey levels?

[Shagg]

Anyone else notice that (further down in the article) they measured 6 different levels of grey between 'white' and 'black', and 4 of the levels of grey actually measured MORE of a power draw than pure white on the LCD monitor?

Re:Grey levels?

[Hentes]

Shadowing the backlight consumes some power in LCDs, except if the part is dark enough so they can dim the light in that sector.

Re:Grey levels?

[QuasiSteve]

4 of the levels of grey actually measured MORE of a power draw than pure white on the LCD monitor?

That's not so strange in electronics.

Take FETs - undriven they're fine, saturated they're fine, but the Ohmic region you typically (when using it as a switch) want to stay out of because the FET's just going to burn the excess off in the form of heat.

There's a bunch of reasons why some regions may take more energy than others. I wouldn't know what the reason is for the panel they used, somebody more intimately familiar with driver design and panel response would have to chime in.

Re:Grey levels?

[Anonymous Coward]

Car analogy? Brakes dissipate heat only when partially applied. Locked brakes don’t, with or without the vehicle moving, nor do brakes that are fully released (well, aside from a very slight parasitic drag).

Rheostats? Yeah, that’s right. Light dimmers (triac choppers)? You betcha.

The real power-saving web pages

[ortholattice]

The real power-saving web pages are simple and clean ones that that use the least CPU time to load, without bloated Web 2.0 javascript mashups of dozens of irrelevant sites and web bugs that keep track of you. TFA doesn't seem to mention that.

Re:The real power-saving web pages

[Zadaz]

The best enegery saving, battery-life extneing thing I've done is to use FlashBlock. (Or in Chrome set it up to not load any extension without a click.) This has been the difference between getting 8 hours out of my laptop and getting 2 1/2.

Now if only web pages would be smarter about using setTimeout.

Organic LED

[Anonymous Coward]

When people have monitors that use organic LED's then it will make a bigger difference. It will also extent the operating lifetime of organic LED's.

What about the CPU?

[queazocotal]

Firstly, I'm extremely skeptical of one of the conclusions - 'flash will make a CRT monitor use more power' - which I just don't believe - it will use an amount of power dependent on the average screen brightness - which may be an increase over black.
LCDs are different - the panel does actually take some energy to change state, and the lag compensation circuitry will use more in motion.

Secondly - a huge part has been missed out of this.
Power consumption of the computer.

Flash, or javascript, even in the background, can considerably increase power.
For example, I just closed all of the flash/animated things in the background on other tabs in firefox, and the CPU usage is now bouncing around 2%, with the computer using 17W.
If I start up a new tab with some flash, and gif animations, it goes up to 25W. (+8W)
Even switching away from the tab only takes it to 23W or so. (+5W)

It would be interesting to work out the total electricity wasted by common flash ads.

Mobile Applications

[DontLickJesus]

With recent changes in browser specs to allow for monitoring of battery levels, I've really taken an interest in this debate. Consider a web based application which has a critical function to complete, yet the battery is dying. Said application could switch it's color scheme to something darker in order to conserve battery and allow that function to complete before draining the battery. It's an edge case scenario, but mobile apps offering a "low power" mode would be a great way to promote usage.

Re:No shit...

[QuasiSteve]

I don't really see the problem with "not insignificant".

Just because something is "not insignificant" doesn't make it "significant".

Say I give you a papercut. You'll be in a "not insignificant" amount of pain.. in fact, you'll probably curse me all day long.
But it's not exactly a "significant" amount of pain either.. it's not like you're curled up on the floor begging for somebody, anybody, to put you out of your misery or at least give you an OTC painkiller.

Perhaps a completely alternative term could have been used - suggestions?
( I used 'measurable' in another post - but while 0.01% might be measurable, it but would be insignificant. )

AOL

[Anonymous Coward]

I expected AOL to suck more energy.

Yup; But don't start me on ads

[Anonymous Coward]

I monitor the electricity my 46" LED TV uses (even in it's most power saving mode). Dark scenes use about 20 watts, white scenes use the full 54 watts. Never actually measure my X220i ... dammit. I did it for charging, using while charging. I use much less power when the notebook is permanently plugged into a power source.

The big thing with web pages though are the fucking ads. Some of them make a cpu core shoot to 100% and stay there.

What about the rest of the computer ?

[Alain Williams]

It would have been interesting to include the whole computer in the power measurement. How much more electricity is drawn by a javascript infested site than one that is just static HTML and images ? How much more is drawn if there are 100 components to build the page instead of 20 (don't forget to include the consumption of your broadband modem, etc, ...) ? How much more electricity does flash use ? How much more through heavy use of AJAX ?

The biggest difference that they showed was that the use of a glass monitor was about double that of a LCD. With an LCD the CPU/... consumption would be a bigger fraction of the whole thing.

Re:What about the rest of the computer ?

[formfeed]

It would have been interesting to include the whole computer in the power measurement. How much more electricity is drawn by a javascript infested site than one that is just static HTML and images ?

Agreed, add the server load to that, for serving static pages versus large pages that call up components on five different servers and deliver tracking information to databases on three more. And the fewer virtual servers you can run on each machine, the more hardware will be needed. Add memory requirements on either end, ram as well as server storage and swap on the client side....
... I think one could easily come up with a quite drastic example.

Is this even a thing?

[squiggly12]

I can't imagine with current LCD's that this would even matter.

Depends on your definition of significant

[Hentes]

A 11% difference between full white and full back is more or less insignificant to me.

I could save $0.18/mo

[Anonymous Coward]

3.8 Watt * 12 hours / 1000 (watt per kw) * 30.5 days/mo * $0.13 /kWh = $0.18/mo

Yippie. Where can I spend this enormous bounty?

Re:No shit...

[Anonymous Coward]

I am more likely to say 'non-trivial' than 'not insignificant.' Based on the simple scale of "undetectable trivial minor light moderate serious" which works well enough for 4 series of D&D spells. There's another step above serious, but it always has a distinct term, and uses a slightly different mechanic than the more fundamental spells. (Haha! I will cast my level 1 spell: Mass Cause Trivial Wounds! *Rolls 1d20, gets 19* ok, you feel slightly uncomfortable, no combat effect)

Re:No shit...

[Anonymous Coward]

Yeah there's a subtle difference, but it's still kindof a pain to read.

As for the project... whatever, so making an ALL black page makes a small difference in monitor power, depending on the model, for the 2 seconds you spend on any given site. Meanwhile, nobody wants to visit your awful site.

Still no compelling reason to make your site in all black... I don't care how "green" you want to be.

2 issues with smartphones

[Nyall]

Some phones have OLED screens that consume less power when displaying dark colors.

Another reason is nighttime usability on a smartphone. Too much light is blinding after your pupils have dilated to accommodate the dark.

Reduce http hits and HTML complexity first?

[Kergan]

Meh... What I'd want to know is, by how much do you decrease a site's power consumption when you strip out:

1. Needlessly complex HTML. (sidebars, header, footer, occasionally content...)
2. Scripts, CSS files and cookies from all over the place (I'm looking at you, ads)

Or to put it another way: Give me what Safari Reader gives me, plus a few nav links, and I'll be happy.

Re:No shit...

[Anonymous Coward]

Significant and insignificant are statistical terms. Significance is a mathematical measurement of the probability that something has occurred by chance. In one sense, significance is a measurement of the magnitude of an effect in comparison to the precision of your instruments, the size of your sample, and the variance of an effect.

But in no sense is significance useful as a stand-alone measure of the size of an effect. Your papercut example is completely and totally wrong. You seem to have absolutely no idea what you're talking about.

However, after reading the article, I see no measure of significance anywhere. I have absolutely no idea what the editor thought he was talking about.

Re:No shit...

[Anonymous Coward]

Black is beautiful, cracker.

Offset against heating costs

[safetyinnumbers]

Isn't 'waste' heat from electrical devices helping heat the room? So this is only a waste in places that are too hot and use fans or a/c to compensate.

ever heard of a false economy?

[Surt]

Manufacturing glasses and medical treatments for all those poor saps looking at black screens is going to more than eat any short term monitor energy savings.

1st released in 2004: Samsung SyncMaster 192MP

[Anonymous Coward]

Why are they using an LCD from 2004?

I would rather see some results based on a monitor that is still in production. Maybe something with an LED backlight or dynamic contrast.

Biblical reference explained

[KingAlanI]

Matthew 7:3-5 is the part about splinter in one eye/beam in another. Not just a failed little/big distinction, but also hypocrisy: criticizing someone else's little problem while ignoring one's own big problem.
I knew the proverb, but hadn't known the chapter and verse, I put 2 and 2 together based on the context of your post.

Re:No shit...

[Anonymous Coward]

Came for the tongue-in-cheek racial undertones, left satisfied.

Honestly, I was really expecting some AC to post something like "Here's a good slogan: Blackle - Google for black people" or something goofy like that.

Disclaimer: I am black, so that means I can say the n-word and you can't.

reading speed

[doug141]

Funny, but it brings up the issue of reading speed. The researchers did not test if people read Blackle at a different rate than Google. For me, white text on a black screen is a slower read, so google wins.

Re:No shit...

[cyachallenge]

Measurable is certainly a better term that could have been used. "Not insignificant" itself should be reserved for unmeasurable topics. Pain is a good topic for the discussion of "not insignificant" because pain can be ambiguous and related contextually in the "of the moment" kind of way. We can talk about how a pain can be intrusive, however in degree of displeasure it is minor. An intrusive pain would be not insignificant when the pain is reoccuring, much like the papercut reference. In the case of something that can be measured in mathematically relevant terms we should say "marginal" or talk about the average battery savings across the board.

Anyway, we're getting off topic the article states "although the difference is just 17.7W and 3.8W for CRT and LCD respectively" and we can see that's a significant amount of power. Particularly for the CRT monitor, 17.7W we're talking about quite a few watts. CRT monitors are almost certainly reserved for desktop environment rather than laptop, however power savings come in the form of money alone, rather than battery life. I would be interested in laptop measurements as the article is only related to desktop monitors. I imagine the 3.8W is much closer measurement towards what a laptop would give us. Laptops can run on 60W without much trouble and I could see 3.8W being important.

I save power on most ALL webpages... apk

[Anonymous Coward]

By disallowing adbanners to run, as well as javascript (where unnecessary). They're ALL "power-saving webpages" for me (as well as faster, & more secure).

Additionally? Since I use what's below, I get there FASTER, SAFER, & just overall, better + more reliably...

APK

P.S.=> How? Simple: The custom hosts file I utilize for one!

(1,772,964++ entries currently, vs. known bad host-domain names (which IS the majority of what you use, hence the DNS system itself being in place, faults & all, as well as malware makers because these are RECYCLABLE, & the RBN was doing it like mad) & growing CONSTANTLY via a DelphiXE2 64-bit system I've rewritten for the 5th time since late 2003)

That, & then even "layering in 'defense-in-depth'": AdBlock addons for FireFox + Opera, IE TPL's for IE...

(Even though they're less efficient than a hosts file which is merely a filter for the IP stack running in PnP designed Ring 0/ RPL 0/kernelmode vs. browser addons running as 'extra-weight' on usermode/ring 3/rpl 3 webbrowsers)...

HOWEVER - AdBlock can't 'speedup' my access to sites that are my favs. as hosts can via "hardcoding" those favs entries in it, & adblock won't protect external to browser email programs (like Outlook) either... neither can firewalls on those 2 items.

Anyhow/anyways:

Between those 2 measures (custom hosts files & using javascript judiciously only)?

I am NOT 'burning more power, CPU cycles, RAM, & other forms of I/O (as a local DNS program would (faults in recursive mode especially) OR a separate system doing so)

"Nothing rides for free", but when I have 'passengers' that set the rest of my 'riders' @ risk, or suck up power they could use too? OUT THE DOOR THEY GO... as dead-weight - hence no local DNS server running here (no thanks, I've seen TOO MUCH of them being DNS-poisoned redirected)... but?

I do use them, external to my system & in a "layered triumvirate zone-defense type formation", & GOOD SOLID filtering ones vs. malware, phishing, & the like:

Norton DNS:

198.153.192.1
198.153.194.1
198.153.192.60
198.153.194.60
198.153.192.50
198.153.194.50
198.153.192.40
198.153.194.40

OpenDNS:

208.67.222.222
208.67.220.220

ScrubIT DNS:

67.138.54.100
207.225.209.66

Layered into BOTH my hardware-side router(s) & my IP stack settings in Windows for DNS servers...

And... there you are!

Oh, how could I forget this: Prepare for the "trolls" & their ad hominem attacks, & effete 'retaliation' vs. my statements here, via down moderations of this post, lol... call it a "hunch/prediction", or just a trend I've noted whenever I mention hosts files (wonder what they're afraid of?)

... apk

Re:No shit...

[Surt]

How about 'small'.

1998 called....

[Anonymous Coward]

Did anyone here actually believe this? The big power draw is from the backlight, which is still running even with black pixels. ...and not only does it wants its "fashionable black webpages" back.... it also wants its CRT monitors back (which do draw a teeny-tiny amount less current to display a black screen).

Re:No shit...

[Anonymous Coward]

My favorite "N-Word" is nilpotent

Re:No shit...

[Anonymous Coward]

Significant and insignificant are also English words. In this article they are used as such. While "significant" and "not insignificant" technically have they same meaning, due to biases in the way people interpret things they come across differently. The article does give power consumption figures and from them I personally would say that the CRT power savings are significant and the LCD savings measurable but not significant, even if they would be significant mathematically since we are not doing statistical analysis or submitting a science paper, but just casual journalism.

Re:No shit...

[K. S. Kyosuke]

I see you have not been introduced to the marvelous invention called "a shower".

Saving a penny every five hours!

[Dr. Gamera]

Quick back-of-the-envelope calculations: Blackle saves roughly 18W over Google; my electricity costs about $0.12/kWh; so Blackle would save me roughly a penny for every five hours that I'm on the Google website!

Re:No shit...

[QuasiSteve]

Significant and insignificant are statistical terms

I think that may be subject to the intended audience.

Looking at what various definitions make of 'significant'..
https://www.google.com/search?q=significant&tbs=dfn:1 ..its use in the article, and my use, seem appropriate.

What muddies the waters is, of course, that they did actually collect statistics.

But I would imagine that the article wasn't written for statisticians, but rather for the layman. In which case, I know exactly what I'm talking about ;)

But if you want to debate further, here's a few other words... theory (layman: hypothesis, science: no no no!), piracy (off the coast of Somalia vs copyright infringement), hardness (materials science).

Tiny amendment/correction... apk

[Anonymous Coward]

"neither can firewalls on those 2 items." - by Anonymous Coward APK on Thursday April 19, @05:30PM (#39739205)

Make that 2 a 1, regarding speed up that hosts can yield for host-domain name resolutions.

* Sorry about that - I can't give the 'nitpickers' around here a "hWnd" on me to grab ahold of, lol!

For the "Cardinal Richelieu" of you trolls out there, and YOU KNOW WHO YOU ARE, lol:

"If you give me six lines written by the most honest man, I will find something in them to hang him" - Cardinal Richelieu

APK

P.S.=> Now, it's back to my spaghetti & sweet italian sausage meal... good stuff (God bless Italians is all I can say, best cooks on the planet)...

... apk

Re:No shit...

[Anonymous Coward]

Well but... when I asked her if it washes off, she slapped me in the face.

If you believe this ........

[Anonymous Coward]

did you know Hippos fart out of their mouths???? No really they do. I heard it in a movie once.

Opposite true with LED backlighting or OLED

[kimgkimg]

I can see the opposite of this being true with LED backlighting (where a portion of the backlight is turned off to make blacker blacks) or OLED where the individual pixel is not being turned on. For standard LCD screens with a CFL backlight (where the backlight is always on), I don't see this being true at all. If anything, for standard LCDs, screens with motion banner ads would consume more display energy as the LCD pixels would need energy to be constantly flipping to update the animation on the screen (so running an ad blocker could make you greener!)

Is there some reason...

[John Hasler]

...you can't just set your foreground and background colors appropoeriately?

Re:Is there some reason...

[Anonymous Coward]

Some people would like sites to look like they were actually designed to be the way they are. Setting background to black messes with most images and can clash css style colors.

Re:Is there some reason...

[skids]

Yes. Most apps/themes and websites/browser-defaults are never tested with a light-on-dark color combination. On many sites the default colors are totally overridden by explicit CSS styles. On some, some widgets are overidden, while others follow the browser defaults, so you get things like textboxes with black text on a black background.

Orwell Sez...

[QuincyDurant]

One can cure oneself of the NOT 'UN-' formation by memorizing this
sentence: A not unblack dog was chasing a not unsmall rabbit across a not ungreen field.

--Politics and The English Language

Re:Orwell Sez...

[grcumb]

One can cure oneself of the NOT 'UN-' formation by memorizing this sentence: A not unblack dog was chasing a not unsmall rabbit across a not ungreen field.

--Politics and The English Language

Not bad. You could do far worse than read the entire piece. There are few more significant essays on post-War English usage.

Not to mention this recent article...

[t4ng*]

Anyone remember this article that was posted a not insignificant period of time ago?

Smart meters reveal what you're watching

Save even more power

[Megahard]

Set your background to black, and all your text so it only displays half the time.

Re:No shit...

[crutchy]

if you weren't a complete wanker you would probably just say "it hurts a bit"

Where's OLED, Plasma, eInk and Projector?

[Mike Zilva]

Just 2 obsolete technologies being tested? OLED is the future in Picture quality and energy saving, so where is this technology represented there? there are 15" OLED LG's TV's and there will be 55" from Samsung and LG later this year. Plasma also have best picture quality for big TV's at the moment. I'm sure Plasma, OLED and CRT (all emissive technologies with better Picture quality) can save a big part of energy when showing large dark screen areas. I'm tired of white backgrounds for everything in computers trying to replicate the paper. But unlike paper, computer monitors emit light and we keep hours staring at them :(

Re:Where's OLED, Plasma, eInk and Projector?

[Mike Zilva]

Try to repeat the test with a Galaxy Tab 7.7 (AMOLED screen resulting in best picture quality in tablets at the moment) and see the real difference it makes in power usage. I would love to see a fast change in content designers to start using black as background for all digital content, at least give us an option to do so without add-ons that may break all the color interaction...

Fine with me

[PPH]

And how about green text and a blinking cursor?

MOD PARENT UP!

[Anonymous Coward]

Ought to be +5 Informative.
There's more power to save on the computer side, where the rendering happens. Some of the websites I've had to use can peg one CPU thread on an Atom, or a core on a Neo. I've seen pages that left the CPU idling at 20-30% (animated GIFs and JS, mostly).

Coincidentally, does anyone else prefer the old Google (which I now get running XLinks2...)?
Or has anyone else looked at the source code for google.com?

(And no, *I* don't have a slashdot account--just agree with the poster)

Can't believe this is being posted today

[kgskgs]

I already did this a long while back. Not only the color displayed on the screen matters for power, but even contrast and brightness settings also make difference. Higher brightness setting of the monitor result in more power consumption.

The results are posted here.

http://kedarsoman.wordpress.com/2006/11/21/saving-energy-one-monitor-at-a-time/

Lighter

[Narrowband]

Boss to Dilbert: My laptop is too heavy.

Dilbert to boss: Try deleting some files to make it lighter...

Please!

[Anonymous Coward]

A black Google? Please, won't somebody think of the pigeons?!

Dark web designs ?

[Anonymousslashdot]

The web pages on my screen are already dark, because I use a plugin for the Firefox browser which has this to say in the description field:

"Changes color combination for energy saving on CRT monitors"

And no, I'm not using a CRT and neither do I care how much power does my display drain to display a web page. It's just that I find green text on black easier on the eyes.

Re:Dark web designs ?

[Overzeetop]

And makes you feel like you're looking at the Martrix. Blonde, brunette, redhead...

Re:Dark web designs ?

[Anonymousslashdot]

Actually, reminds me of that green chick that young Kirk dated in the newest Star Treek reboot. Must be that I like that type...

All that for a possible $1.28 Savings!!

[JFilz]

Sent this to the Author:

Just read "Blackle vs. Google Monitor Power Consumption Tested".

Compared the worst and best (for LCD - who still used CRT??) is about 4w of difference. Compared that to a user (such as a office worker who uses a PC
and internet all day at work) and can work in nearly total screen blackness to achieve this saving. Averages 8 hours of PC screen time a day. There is 365 days a year (not counting weekend or holidays-he may work at home or watch PC based TV - Who knows!!) Thus 4w 'saving' (which is per hour) X 8
hours per day X 365 Days = 11680 watt hour or 'wh' worth of power 'saving'.

Now consider electrical companies charger per 1000 w or by kw.... so that is 11.68kwh of saving.
National average charged is $0.1099/kwh (as per http://www.eia.doe.gov/cneaf/electricity/epm/table5_6_a.html) so that is
$1.28 savings (PER YEAR!). That is if you can read a nearly all black screen.

My coffee to keep my bugged eyes open enough to view that screen is more than that per day. Not to mention the DAMAGE to my eyes from squinting
trying to read or watch the PC.

Better yet - use a power setting to turn off that 34.8w to 38.4w LCD Screen after lets say 5 mins - will save nearly 10 time the power than when you view a Dark gloomy hard to view website. BOTH option will give you a BLACK screen to view!!! LOL! Good WORK!


And he responded:


I still use a (good) CRT for photo editing... it has better colour than an
LCD can display. :-)

Thanks for the comments, I don't disagree with anything you say. We were more interested in testing the claims Blackle was making... while there is a
mathmatical difference, how relevant that figure is an entirely different question.

Cheers,

Max


NOW who wants to "save" UP to $1.28 per year on power - but end a life squinting at a dark screen only

Re:All that for a possible $1.28 Savings!!

[ceoyoyo]

Huh. He replied hey? You should have sent:

Dear Author,

Ever heard of error bars?

Re:No shit...

[Beeftopia]

Say I give you a papercut. You'll be in a "not insignificant" amount of pain.. in fact, you'll probably curse me all day long.
But it's not exactly a "significant" amount of pain either.. it's not like you're curled up on the floor begging for somebody, anybody, to put you out of your misery

Speak for yourself, buddy.

// low pain tolerance.
// you monster.

Not as black and white

[Anonymous Coward]

On a TFT monitor it's not as black and white (pun intended). Most TFT's pixel are actually default transparant. Try switching on the backlight of a laptop tft without the screen power and data cables plugged in, it's likely to be white. In this case a white picture uses less power (10-15%). Some displays also dim their backlight when the screen is entirely back (this allows the manufacturer to enormously boost the stated contrast ratio without improving the display). Here you can save with a black background, even if the lcd is default white.

A CRT monitor obviously uses less power when displaying no image, since the intensity is directly related to the CRT beam current.

Re:No shit...

[thePowerOfGrayskull]

You may keep your geek card for another day.

for loops

[biodata]

This is the reason why 'i' is the default name for a loop variable. i is the most energy efficient variable name in a white on black world.

They just might know English better than you...

[jeffb (2.718)]

Ah, for the days when most people were literate enough to recognize, never mind use, rhetorical devices like litotes.

Re:They just might know English better than you...

[Seven_Six_Two]

Aaw. You got there first. I posted below about litotes, but didn't remember to sign in first. My loss, and good one!

Readability: yes, please.

[jeffb (2.718)]

Oh, so very, very much this.

Let me count the problems with light-text-on-dark-background:

1) If you have cataracts, corneal irritation, or smudged glasses, bright objects against a dark background are MUCH harder to resolve than dark images against a white background. With black-on-white, you just get reduced contrast; with white-on-black, you get distracting smears and rays all over the page.

2) In a dim room, your pupils dilate more if the scene before you is mostly dark, and dilated pupils generally produce poorer acuity. A bright background causes your pupils to contract, and just like stopping down a cheap camera lens, it improves the focus of the image hitting your retina.

3) In a bright room, a mostly-dark display will be more obscured by reflections and glare.

This is one reason I stopped hanging out at dpreview.com. Yeah, I know, photographers think their stuff looks better against a black background, but more than five or ten minutes on the site gives me a headache.

Re:Readability: yes, please.

[Anonymous Coward]

Proof for claims please.

Re:Readability: yes, please.

[Anonymous Coward]

1) If you have cataracts, corneal irritation, or smudged glasses, bright objects against a dark background are MUCH harder to resolve than dark images against a white background.

Try grey on black. It reduces the contrast, and works. Really.

2) In a dim room, your pupils dilate more if the scene before you is mostly dark, and dilated pupils generally produce poorer acuity. A bright background causes your pupils to contract, and just like stopping down a cheap camera lens, it improves the focus of the image hitting your retina.

And when you turn your head away from the monitor, you'll get eye strain when the eyes have to adjust again.

I think a good solution is monitors that adjust their brightness based on ambient light. (A few manufacturers do those -- Fujitsu and Eizo at least)

Re:Readability: yes, please.

[Zinho]

2) In a dim room, your pupils dilate more if the scene before you is mostly dark, and dilated pupils generally produce poorer acuity. A bright background causes your pupils to contract, and just like stopping down a cheap camera lens, it improves the focus of the image hitting your retina.

That's not true for everyone. I checked wikipedia's entry on photographic F-stop, and it suggested that the acuity issue you're experiencing is due to lens defects, as they dominate distortion at large aperture. (note to self: I should have guessed that from point 1 about cataracts...) For people with good lenses, though, bright light reduces acuity as diffraction dominates the distortion at small apertures.

I'm sorry for your eye condition, and you're welcome to continue using a bright screen if that helps you. Please understand, though, that this isn't a one-size-fits-all situation, and don't hate me for using a dark screen if that's better for me.

Re:Readability: yes, please.

[studog-slashdot]

1) If you have cataracts, corneal irritation, or smudged glasses, bright objects against a dark background are MUCH harder to resolve than dark images against a white background. With black-on-white, you just get reduced contrast; with white-on-black, you get distracting smears and rays all over the page.

I can't comment on the eye conditions, but maybe clean your glasses? That works for my glasses anyway.

2) In a dim room, your pupils dilate more if the scene before you is mostly dark, and dilated pupils generally produce poorer acuity. A bright background causes your pupils to contract, and just like stopping down a cheap camera lens, it improves the focus of the image hitting your retina.

In 2 decades of BoW vs WoB debates, this is the first reasonable argument I've heard for BoW. OTOH, if using WoB causes you eye not to be able to focus, you need to get to an optometrist.

3) In a bright room, a mostly-dark display will be more obscured by reflections and glare.

I've never had a problem with glare/reflections except when in direct sunlight, which hurts both BoW and WoB equally. Also, when I've had a hard-walled office I keep the lights off. More earth-friendly, cooler, and nicer to work in.

Re:Readability: yes, please.

[jeffb (2.718)]

Well, to the extent that my eye condition is that I have natural lenses and corneas, I agree, and accept your condolences.

I've read the same discussions of acuity, and many more. If the human lens and cornea were optically perfect, yes, a wider aperture would produce a clearer image. Unfortunately, they're actually not very good at all, no offense to any Intelligent Designer who may be reading.

We have the impression of sparkling clear vision for several reasons. We normally use only the central part of the lens, which (as you've read) tends to de-emphasize optical weakness. Our most sensitive spatial resolution comes from the fovea, which rests at the center of the lens's focal field; again, that's where distortions are least prevalent. And, once an image does fall on the retina, it gets image-processed to hell and back by the retina itself, the optic nerve, the visual cortex, and big chunks of the rest of your brain to boot.

If a dilated lens produced the best spatial resolution at the retina, we'd expect that the sharpest things we could see would be isolated bright objects in a dark field. Things like the moon, or stars. As it turns out, though, we don't resolve those things very well at all. That's why we get vague impressions of "the man in the moon", and that's why so many cultures talk about stars having points.

I certainly don't hate anyone for preferring light-on-dark. I'm just trying to point out that there are legitimate physical reasons that light-on-dark poses problems for a lot of people.

Re:Readability: yes, please.

[jeffb (2.718)]

1) If you have cataracts, corneal irritation, or smudged glasses, bright objects against a dark background are MUCH harder to resolve than dark images against a white background.

Try grey on black. It reduces the contrast, and works. Really.

It'll reduce the smear/spike effects, but it'll also reduce legibility. Contrast is critical for resolving fine detail. (I have been thinking in terms of reading text, not, say, playing Pac-Man.)

2) In a dim room, your pupils dilate more if the scene before you is mostly dark, and dilated pupils generally produce poorer acuity. A bright background causes your pupils to contract, and just like stopping down a cheap camera lens, it improves the focus of the image hitting your retina.

And when you turn your head away from the monitor, you'll get eye strain when the eyes have to adjust again.

Fair point, I suppose, although I never seem to have trouble with it myself. Maybe it's just that rooms aren't usually that dark -- which, if true, weakens my original point anyhow.

I think a good solution is monitors that adjust their brightness based on ambient light. (A few manufacturers do those -- Fujitsu and Eizo at least)

Maybe, but I've had to disable that feature on iPads and my work laptop. The lower-brightness settings just aren't legible enough. If you're in your twenties, your mileage will vary -- but, trust me, this is one of many ways that getting old sucks.

Re:No shit...

[Anonymous Coward]

I haven't seen any green people.

As good a time as any

[__aaqvdr516]

This is as good a time as any to post a link to something I've used for well over a year now.
http://stereopsis.com/flux/

It automatically adjusts the color temp of your monitor to reduce eye strain at night. I suppose it has the side effect of lowering power consumption as well.

On Windows/Mac/Linux and pads.

No, I don't work for these guys nor am I paid by them. It's just that good.

Black uses more power for me

[viper66]

I tested this using a Kill-A-Watt meter and three Dell P2210s. The results were 56W showing google.com on all three, and 59W showing blackle.com on all three.

If they want to save power...

[identity0]

How about less Java, flash, and videos?

CPU and network still takes power, too...

Re:If they want to save power...

[robsku]

I applaud for that! +javascript, it's the worst when the page has no java or flash applets, no videos and yet consumes 99% CPU for unnecessary and downright annoying AJAXy stuff on background in amounts that "excessive" is a tiny word to describe it.

Bad JavaScript can be a real energy hog

[Anonymous Coward]

Some poorly written webpages use lots of CPU to run silly animations. Like this one for example:
http://www.babs.unsw.edu.au/staff_research/dr-federico-lauro
Not only does this waste energy, it's annoying when your laptop fan revs up and makes a bunch of noise.

Re:No shit...

[WaywardGeek]

Mobile devices like the original iPhone had a black background for good reason. It conserves power. I always view my computer screen in inverse video, not to save power, though it does extend battery life on my laptop a good deal. I need the improved readability that white on black provides. People with low vision universally prefer white on black. The whole black on white background is an unfortunate hold over from dead tree publishing. And likely as not having Stargardt's Disease, I want as few photons lighting up my retina as possible.

So, I hope this whole stupid Apple white page thing goes the way of the dinosaur. Life was better when it was green on black.

Re:No shit...

[OakDragon]

Is that you, Minister Farrakhan?

Re:No shit...

[GreyWolf3000]

If you were black, then you would have used the n-word, instead of simply referring to it. So that tells me you're as white as I am.

This should offset my SETI account

[bastian74]

Finally a way to offset maxing out my GTX580 and Core i7-2500k at 100% 24/7

Null and void for me

[davydagger]

I've measured average use of my 17" LED backlit LCD screens at 8 watts a piece(2 of them), with 16 max in torch mode.(per spec). it might make a diffrence if you are using other technologies, but for the common joe, just get a low power monitor(s)

Eye savings

[arbulus]

It may not save energy, but dark backgrounds save my eyes. I always love when sites use darker themes. Bright white backgrounds on a 24 inch monitor are very very painful, no matter how far I turn down my backlight.

Sometimes black uses MORE power.

[Dialecticus]

Assuming that any dynamic backlighting features are disabled, a typical TN panel will use slightly LESS power on an all-white screen than on an all-black screen.

LCD panels comes in more than one flavor. The cheap and common variety is called TN (Twisted Nematic). A TN pixel is transparent/white until power is applied to it, at which point it turns opaque/black. This means that it takes some small amount of power to make a pixel turn black. A less common, more expensive technology is called IPS (In-Plane Switching). An IPS pixel is opaque/black until power is applied, at which point it turns transparent/while. There are also VA (Vertical Alignment) panels, and I don't remember off the top of my head whether they're transparent or opaque when not powered.

I just ran a test with a power meter of my own, and the IPS-based LCD monitor I'm using consumes 17 watts when displaying an all-black image and 21 watts when displaying an all-white image, and the backlight is not responsible for any of that difference. Tests I've done on a previous TN-based LCD monitor have shown an opposite result, as is to be expected. The thing is that TN panels are far more common because they're cheaper to produce. So if the entire world tries to use use dark web pages in order to save power, then a few people with IPS panels will use less, but the vast majority of users will be be browsing on TN panels, and these users will actually be using slightly MORE power. And, given their greater numbers, I suspect the average power usage would actually go up.

And as long as there are any white or brightly colored pixels onscreen, be they part of the taskbar, the browser's title bar, or the web page itself, then dynamic backlighting shouldn't be much of a factor, either. The backlight can't be turned down any dimmer than the brightest pixel. (This excludes LCD monitors with backlights that are capable of zone-dimming, but those are exceedingly rare.)

Re:No shit...

[Anonymous Coward]

If you were black, then you would have used the n-word, instead of simply referring to it. So that tells me you're as white as I am.

I am white and i have no problem saying nigger. It's jsut a word, deal with it.

Wrong

[dutchwhizzman]

How much trouble do you think power companies are having to keep voltage and frequency of the AC net within nominal parameters? They constantly juggle with the amount of fuel and sometimes the amount of power plants connected to the grid. The amount of electricity produced is exactly the amount that is being demanded, nothing more, nothing less. If that wasn't the case, you'd be paying for every kWh you could possibly consume, because they had to produce it for you, whether you use it or not.

Re:Wrong

[rev0lt]

Electricity production is done by provisioning i.e.there is an expected average consumption, to which is added a safety margin. Transformers and conductors in general aren't very good at working in stress, and that is what usually happens when there is a peak in demand and the grid is unable to respond quickly enough, so it's not a good idea to break those just to save fuel. There are also losses in transport, and those are difficult to calculate (yeah, I know, you can calculate them _exactly_ at 25C), because cable impedance varies with temperature and environment humidity.

Energy usage generating the page?

[dutchwhizzman]

What about the amount of energy used to generate the page at the web server? Big, dynamic web pages requiring lots of database hits, disk IO, cpu cycles cost more energy to generate. Large pages cost more energy to transmit over networks. Complicated javascript pages, flash and java content cost more energy to generate on the computer that has to render them to display them. The same applies for compressed media, like images, sound and movies. Animated media costs more than static media too to display. Has anybody looked at those factors?

Re:No shit...

[Anonymous Coward]

Noticeable.

Hipster Fizzl

[Fizzl]

Bah, I was using red and neon green on black bacground (with twinkling stars) on Geocities before it was cool. I think my Yellow and Black "Under Construction" ribbon consumed someones 14" CRT energy thou.

...turns out there is a not insignificant difference

Very crafty! I couldn't decipher that double-negative sentence fragment, so I had to actually read the article to come into some kind of conclusion myself!

double negative *GN*

[Anonymous Coward]

"not insignificant difference" so that would be "significant difference" then.

Re: Yes way shit...

[qubezz]

The above post has incorrect assumptions.

Standard LCD screens do not alter the intensity of the backlight based on the information displayed on the screen, and the backlight and it's inverter is the majority of the power consumption. In addition, the drive circuit that aligns the liquid crystals can work opposite from how you expect in a TFT. Most TN screens, for example, are white or light gray when unpowered - refreshing the pixels to a black state takes more transistor drive than making the screen white. This is the technology you will find in most portable devices and computer monitors.

Some LED-backlit TVs use dynamic backlight, or even zone-dynamic backlight, where (mainly to create ridiculous contrast ratio specs) the backlight is reduced to the maximum temporal white level needed, or for multi-area addressable systems, the brightest backlight needed in an area.

The only portable devices where the brightness of the screen data is directly related to energy consumption would be those with OLED screens (such as the Samsung Galaxy SII line). The individual pixels are miniature LEDs, and when a pixel is black, they are turned off. On these AMOLED display phones, a black wallpaper can use far less power.

When I think of "power-saving webpages", I may be more concerned about one that runs my CPU at 100% for several seconds to display a page, Slashdot.

Not only one

[SuperKendall]

Whatever the reason, white on black=bad (and I'm sure I can't be the only one).

You are not, I don't know about an afterimage but I can't read white on black text for more than a few minutes. It really hurts my eyes.

Maybe that was only true on CGA monitors...

Exactly, we need something more than one test performed in the 60's with a dumb terminal! Or whatever it was that supposedly "showed" that.

In the meantime I will keep my white background and my sanity thank you very much.

P.S. make a note of how many people that claim to like dark backgrounds wear glasses...

Re:No shit...

[asylumx]

This.

Stop saying "This." It's not a statement. It provides no context, especially in the case where your parent post is not modded up, and Slashdot provides a way to easily quote the parent using blockquote tags. It makes you look pretentious and douchey, so stop "This."-ing.

Science Re:Seriously?

[Anonymous Coward]

The LCD they tested is also 8 years old.

I'm not saying newer LCD screens would perform differently (dynamic contrast, local dimming, etc. == marketing stats boosting and terrible) but basing a blanket statement like "B) Websites with darker colours tend to cause the monitor to consume less power." on a test with one LCD monitor is stretching it.

You're right. However now you're questioning their rigour and you aren't giving them credit for what they have accomplished. They challenged and tested a hypothesis. And they found something interesting which has sparked controversy. Should more tests be done? Absolutely, but for what they've contributed I think we should, "show them some love. In the meantime, it wouldn't hurt to use a custom css to make google have a black background (or any of your favourite websites).

E Ink FTW

[ak47gen]

Read this article in E Ink FTW!!!!!

Re:No shit...

[bwcbwc]

If we figure google gets about 1/2 billion searches per day world-wide and each search conservatively takes about 5 seconds to type in and view results, we get a global savings of nearly 2,300 kW-h per day. Typical US household usage is on the order of 1000 - 2000 kW-h per month, so this is enough energy to power about 50 US homes and nearly double that number of homes in more conservation-oriented places like Europe. I would consider this number to be on the low end of the actual global power savings, as some sources show google serving 3 billion searches per day (http://www.quora.com/How-many-search-queries-does-Google-serve-worldwide-every-day) , and the watts used will be 5x higher for CRTs.

In the grand scheme of world wide energy usage, this is an insignificant amount, but on the other hand, the effort required to make the switch from white to black background is pretty low compared to other energy-saving efforts, too. What's the saying? "Once you go black, you never go back." Check out HP's corporate site (hp.com) for a sample of how this might look.
( 3.3w*5s/search*500*(10^6) search per day = 16.5*500*(10^6) watt-seconds= 8.25 (10^6) kW-s=2,292 kW-Hours)

LCD monitors don't work that way

[__aaltlg1547]

The way LCD monitors work is that they have a backlight that's on all the time and it consumes the lion's share of the power. Dark pixels are produced by applying an electric field to liquid crystal, an act that takes power mostly in the switching of states. So an all-dark screen takes about the same power as an all-white screen.

If you want to save power in display-related actions, display pages that require minimal computing to render. You'll save more power in the CPU and GPU.

If you want to save power again, set your browser to reject cookies, not display video and not run scripts you haven't authorized. Set your firewall to block major advertisement sites.

And that's just your browser. There's more power to be saved by turning off power-hungry services of your operating system.

Greenwashing

[GameboyRMH]

CRTs and OLEDs need more power to display white than black, but LCDs, the most common kind of screen nowadays, needs more power to display black than white. So black pages actually require more power on average.

Surprised Me!

[Anonymous Coward]

According to their results, a black LCD screen uses 4 watts less than a white one.

I did not expect that. As you said the back light remains on and I assumed the pixel rotation would have been the same.

I'm very surprised by the result. Though I'm also very suspicious of the result due to the source.

I'm wrong apparently

[GameboyRMH]

Wait according to TFA I'm wrong, the LCDs are using less power to display black as well.

Notes from a math/compsci/ee tutor

[Anonymous Coward]

Not that it affects the product (charge/energy), but amps measure transfer of charge over time, and volts measure electrical potential energy, so volts should be the height of the waves (gravitational potential energy) and amps the rate of arrival (in terms of volume of water per unit time, not waves per unit time).

Better, but still has room for improvement. Voltage (volts) would indeed be best represented by wave height in this metaphor, but current (amperes) would be better represented by the length of seashore you're working with. The volume of water per unit time would be power (watts), since power is the product of voltage and current (and the volume of water per unit time would similarly be the product of wave height times the length of seashore you're working with). Rate of arrival doesn't change the power, since waves arriving at a faster rate are necessarily not as broad, and therefore carry just as much water as those arriving at a slower rate, which are more broad. If anything, the rate of arrival of waves would be a good representation of frequency, and indeed, power is independent of frequency (for a simple circuit with no impedence).

Personally, I prefer a 'water in pipes' metaphor, where current is pipe diameter, voltage is water pressure, power is water flow rate, and energy is water volume, but unfortunately this doesn't allow for any intuitive representation of frequency (oscillating water flow?)

Way ahead of the game

[Anonymous Coward]

Maddox, once again proving he actually has The Best Page In The Universe, points out in his faq why he decided to use a black background with dark gray text back in 1997.

Re:No shit...

[Gizzmonic]

Using "not insignficant" instead of "significant" lengthens the sentence and makes it harder to parse. They mean the same thing despite your pointless story about paper cuts. It's never not good to go ahead with stopping not misusing self-contradictory phrases.

The Olmpics in London

[GT66]

may well go down in history as the very first truly Orwellian Olympics. Honestly, why would anyone voluntarily spend money or time subjecting themselves to Big Brother's special event number 1? Maybe Big Brother can make all the athletes wear gray uniforms and refer only to their participant numbers to make it harder for anyone to single out a particular person. They should probably paint all the buildings and fields gray too so to dissuade any uncitizen from gleaning any particular location information for bad purposes.

Re:The Olmpics in London

[GT66]

Bah... wrong article.

Black interfaces are the best.

[wimp_org]

They already figured this out in the hitchikers guide to the galaxy. "Every time I press one of these black controls, labelled in black on a black background, a little black light lights up black to let me know I've done it."

In my living room....

[Anonymous Coward]

On my 50" plasma tv the watts usage is closer to 150w vs 350w depending upon how much color/brightness is currently being displayed on the screen. I've hooked up power monitors and watched the draw fluxuate first hand. Now I don't surf the web on a plasma TV, or a screen nearly so large, so I have to question if its relevant, but I can see that kind of observation creating the fodder that black background web pages could save a lot of energy.

"Great minds think alike"... apk

[Anonymous Coward]

http://tech.slashdot.org/comments.pl?sid=2798327&cid=39739205

APK

P.S.=> I forgot to note I use Opera 12 64-bit build 1380 & it has a FLASH only on demand option I use, and in FireFox (WaterFox &/or PaleMoon 64-bit) also, which of course saves power too...

... apk

Re:No shit...

[busyqth]

This! ^^^

Simple solution?

[Anonymous Coward]

Forgive me if this has been said, but... why not just turn your monitor off? Does anyone really idle on an unchanging website for hours?

MagicBright

[Anonymous Coward]

Traditional LCDs would tend to draw the same power independent of screen content. This particular LCD display has 'MagicBright' technology which modulates the brightness (power to backlight) depending on screen contents... which accounts for the power differences. Perhaps they should have tested a few LCDs to get a more representative sample? It took 2 minutes of 'google research' to figure this out.

Re:No shit...

[Bill Dog]

Nerd thissers : 2011 :: AOLamer me tooers : 1993

Watch the light skin guy

[Anonymous Coward]

Watch the light skin guy

He gets real uncomfortable when the guys says they should kill white people.

Technical Babble

[Anonymous Coward]

Why does this have to be so technical. Turn on your monitor. Set it to white screen...Then black screen...And judge for yourself...The brilliance itself resonates its energy level to what you have to do to save energy. The energy can be felt, depending how old your monitor is. Try it in a pitch black room. Goodness.