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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 ..."
Yes, anyone here actually believed this. I guess in your hurry to post, you misread the double-negative in the summary...
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.
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.
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.
For large sets, this will be our guide even unto death, for the LORD will work for each type of data it is applied to...
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.
"Our two-party system is like a bowl of shit looking at itself in a mirror." - Lewis Black
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.
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