Behind the Numbers: LCD vs. CRT

OrenWolf writes "CNet has an article discussing the difference between CRT's and LCD's - where they've been, where they're going, and what to look for when buying one. They inclde information on how to judge the most important (and most overlooked) features in LCD's, the rise/fall of pixels, something that keeps most gamers away from them." Good summary type piece, although nothing exceptional for the more hardcore techie.

Comments

Everytime

[vinnythenose]

Everytime I see an article about this sort of stuff I keep praying that OLED monitors will be out soon. Flat, less power required than in LCD, flatter than LCD, bright like CRT and once in full production likely up to 30% cheaper than LCD.

Tom's Hardware has an excellent comparison

[Canabinol]

This article over at Toms does an excellent job of describing the technical differences between CRT and LCD.

He also has a recent roundup of the current LCD players and what to look for.

C.

LCD's are horrible for photographs

[PhantomHarlock]

The current generation of LCD displays are terrible for viewing photographs. The square pixels and variable contrast makes for a number of bad artifacts:

1. JPEG compression is terribly magnified on an LCD. look at a typical Yahoo News press photo on an LCD and then on a CRT, especially close ups of people.

2. Contrast is variable from top to bottom while looking dead center: On my recent model VAIO laptop, when looking at the screen from dead center, the top is too dark, the bottom is too bright. (in terms of black level)

3. Colors shift depending on left to right viewing angle, and typically subtle hues of red and blues and purples will not appear as pleasing and natural as they do on a CRT.

4. Overall gamma is poor, with the falloff happening in all the wrong places, which wrecks havok on portraits and figure photography. (which means yes, pr0n!)

So it's interesting to note that on a recent visit to Vertis studios in San Francisco, the people who often do the Macy's catalogs, that each digital photography station consisted of a high end scanning back camera and a macintosh with a 22" LCD monitor! I mentioned this to one of the supervisors and he said "Yea...we're aware of the problems with LCD...we carefully calibrate them and make sure to stare at them dead center, or we get the color shift problem left to right." I figured that someone had sold them on those setups purely for the 'cool' value, and they fell for it hook line and sinker.

He then took me into the finishing room, where, to my pleasure, there were several workstations outfitted with high end CRT monitors with hoods around them. I knew there was no way they were doing catalog work without CRT's, given the pickiness of fashion retailers over the color accuracy in the catalogs.

When I was working at Digital Domain in Hollywood, as well as every other VFX company I've ever worked for, there was nigh an LCD in sight, because you can't do critical adjustment on an LCD.

Despite all this doom and gloom, it IS getting better all the time, and eventually, unless it's replaced by DLP or other "every pixel is a tube" flatscreen technology, then I'll be calibrating my photographs for viewing on LCD, because that's what everyone will have. Until then, I prefer my high end Sony FD trinitron above all else.

--Mike

Re:LCD's are horrible for photographs

[Otterley]

Saying LCDs are bad because you can see JPEG compression artifacts is like saying microscopes are bad because you can see germs in them.

JPEG is lossy compression and always has had artifacting. Because you've never seen it before says more about the blurry monitors you're used to than anything else.

Re:LCD's are horrible for photographs

[2nd Post!]

Not trying to pick an argument, but some thoughts on your opinion:

"The current generation of LCD displays are terrible for viewing photographs. The square pixels and variable contrast makes for a number of bad artifacts:"

I suspect the problems have as much to do with software being optimized for CRTs as much as real problems with LCDs.

"1. JPEG compression is terribly magnified on an LCD. look at a typical Yahoo News press photo on an LCD and then on a CRT, especially close ups of people."

I would argue that this actually says more about the visual clarity of the LCD, in being able to pick up the artifacts that CRTs blur away.

It's akin to claiming that certain brands of cameras with extra high speed film and extremely good lenses are bad for taking portraits because all of the makeup, flaws, and blemishes show up in the photographs, and that it's better to use a slower film and a less precise lens.

"2. Contrast is variable from top to bottom while looking dead center: On my recent model VAIO laptop, when looking at the screen from dead center, the top is too dark, the bottom is too bright. (in terms of black level)"

It is certainly true that CRTs have a wider viewing angle and more uniform color because each pixel is more like a point light source that radiates in a sphere, where an LCD pixel is a cone of light. Newer LCDs, like Apple 15" and 23" LCDs, have much better contrast ratio, 350:1, better viewing angle, 160 degrees in either dimension, and better brightness, at 200 nits, than their older 22" LCD;300:1 and 180 nits. I can't google anything about the VAIO laptops, but it's not uncommon for, say, a ViewSonic 17" LCD to hit 220 nits and a 300:1 contrast ratio; brighter and more evenly lit, but not nearly as black.

"3. Colors shift depending on left to right viewing angle, and typically subtle hues of red and blues and purples will not appear as pleasing and natural as they do on a CRT."

This does have something to do with the viewing angle; as per the 'pleasing or natural bit', that's about color optimization, I believe. LCDs have a different gamut and visual quality than a CRT, and if the software doesn't take that into account, that's like having overhead flourescent lights on a CRT without a hood!

"4. Overall gamma is poor, with the falloff happening in all the wrong places, which wrecks havok on portraits and figure photography. (which means yes, pr0n!)"

Can't speak for that, you may be right about the gamma.

"So it's interesting to note that on a recent visit to Vertis studios in San Francisco, the people who often do the Macy's catalogs, that each digital photography station consisted of a high end scanning back camera and a macintosh with a 22" LCD monitor! I mentioned this to one of the supervisors and he said "Yea...we're aware of the problems with LCD...we carefully calibrate them and make sure to stare at them dead center, or we get the color shift problem left to right." I figured that someone had sold them on those setups purely for the 'cool' value, and they fell for it hook line and sinker."

No, there are real reasons to use a LCD over a CRT, more than just 'cool' value.

Size, energy output, eyestrain-flicker, digital precision (digital input to digital output, consistent guaranteed visual quality across all LCDs if gamut and color space are taken into account, etc), and visual precision (no convergence, alignment, moire, or focus problems).

LCDs suffer from different problems entirely; instead of moire, convergence, focus, or alignment problems, they suffer from narrower visual focus, and lower contrast ratio and brightness. In fact, LCDs are *much* sharper than just about any CRT because there is no alignment, no convergence, no focus problems because there's no reliance on three electron guns aimed at a phosphor coated screen.

You also have the issue that CRTs aren't linear, where an LCD can be made so. CRT electron guns are nonlinear devices between the 0 and 1 signals, while an LCD's ramp between the totally off and totally on signal *is* linear; I'm talking about the value of Red0-Red255, or Blue0-Blue255, or Green0-Green255.

Then there's refresh. CRTs must refresh a line at a time, where LCDs refresh the whole screen at once; less headache, less flicker, less eyestrain.

"He then took me into the finishing room, where, to my pleasure, there were several workstations outfitted with high end CRT monitors with hoods around them. I knew there was no way they were doing catalog work without CRT's, given the pickiness of fashion retailers over the color accuracy in the catalogs."

This will change when designers and fashion retailers start using LCDs; then when you have digital images end to end, you can start seeing more focus on better compression algorithms (ne horrible JPEG artefacting), better gamma and gamut and color space taking advantage of the fact that LCDs have linear color response and deterministic color response.

"When I was working at Digital Domain in Hollywood, as well as every other VFX company I've ever worked for, there was nigh an LCD in sight, because you can't do critical adjustment on an LCD."

You couldn't do it, doesn't mean you can't. There are problems right now, but doesn't mean there also aren't advantages.

"Despite all this doom and gloom, it IS getting better all the time, and eventually, unless it's replaced by DLP or other "every pixel is a tube" flatscreen technology, then I'll be calibrating my photographs for viewing on LCD, because that's what everyone will have. Until then, I prefer my high end Sony FD trinitron above all else."

Yeah, new technologies and software (such as Apple going all LCD) should help a lot.

Re:"Graphics designer would not touch a LCD" -- BS

[John Whitley]

Not only are the Apple Cinema (and Studio) LCD displays coveted by graphic designers and other professionals who do color work, you can actually use external color calibration equipment with them just as is done with CRTs and get reliable results for production printing. This article's information, while accurate for run-of-the-mill LCDs, perpetuates a lot of "old news" about LCD tech that is soon to go by the wayside.

BTW, the stated viewing angle on these is 170 deg, and they darn well mean it. Comparing (e.g.) a laptop LCD to these is wholly inaccurate -- not all LCD panels are created equal these days.

Anyone know of other displays that have managed to ship with panels of this quality?