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New 20" iMac Screens Show 98% Fewer Colors
Trintech points us to an AppleInsider article about another class-action lawsuit directed against Apple Inc. This one claims that the displays on new 20" iMacs are only capable of 6-bit-per-pixel color, 98% fewer colors than Apple advertises. Rather than the 8-bit, in-plane switching (IPS) screens used in 24" iMacs and earlier 20" models, "[t]he new 20-inch iMac features a 6-bit twisted nematic film (TN) LCD screen," according to the article, "which the [law] firm claims is the 'least expensive of its type,' sporting a narrower viewing angle than the display of the 24-inch model, less color depth, less color accuracy, and greater susceptibility to washout." Apple recently settled a very similar class-action suit about the displays on MacBook and MacBook Pro models.
But seriously, yes, LCD (and any decent LCD mfgr) will spec the color bit depth of a panel. A really good mfgr (NEC, LG, Samsung) will have gamut charts available to OEMs and possibly end users. But if Apple chooses not to share, or worse just lies about it, there's not much you can do other than try to do some independent research to figure out what panels Apple uses, then contact the panel mfgr to (try to) get some specs.
everything in moderation
It's 6 bit per color in a rgb scheme, making it 18 bit or 262,144 total.
I'm aging rapidly, I bought a new game and had no idea if my machine was good for it.
I admit I have no idea how to figure out how many colors there are with 6 bits per pixel...but I did find this website which talks about 8bit and 6bit LCDs: http://compreviews.about.com/od/multimedia/a/LCDColor.htm
Pretty much any monitor advertised as 16.2 million colors is using a 6 bit panel with hardware dithering. Those advertised as 16.7 million colors tend to be 8 bit.
6-bit colors? In 2008? What were they thinking? The trend is towards 10 bits. At 6 bits, gradients look awful; false edges appear. Go into Photoshop, generate a single color gradient, and then "posterize" to 64 colors to see what this looks like. Yuck.
Dithering won't help; it puts noise into a nice, smooth gradient.
No, the article just wasn't clear. It actually means 6-bits per color channel per pixel. In other words, 18-bits per pixel instead of full 24-bits per pixel. And the reduction from 2^24 to 2^18 does indeed reduce the number of colors from about 16 million to 262,144 - a reduction of about 98% of the entire color space.
And as someone who owns a 18-bits per pixel monitor, trust me, you can tell when working with static imagery. Maybe not when playing games or playing movies, but you can tell. The little gradients on Slashdot look terrible on that monitor. It helps that it doesn't do any form of dithering, but even on my cheap Acer laptop that also only does 18bpp, you can clearly see the dithering.
Since Apples are frequently used for photo work and print work, using only 6 bits per color channel is simply unacceptable. Coders probably won't care, but graphic artists most certainly will.
You are in a maze of twisty little relative jumps, all alike.
They make the claim that the "display" supports "millions of colors". And by display, they mean something that has 290 cd/m2 brightness and a 160 degree viewing angle -- which could hardly be referring to the GPU/video card.
The wheel is turning, but the hamster is dead.
Technically, you could only define 32 colours of those 64 (from a total palette of 4096!), the other 32 were actually the same colour but at half the brightness, hence the name of the display mode: EHB - Extra Half-Brite. This was very useful since you could use that extra bit-plane as a shadow-plane, and most palettes had dark and bright versions of the colours anyway.
Of course, this doesn't make it any less superior, just saying...
c++;
Mod parent up. This is absolutely true. I'd estimate that the vast majority of LCD panels on the market are 6-bit screens. Whether you are buying Benq, LG, Dell, Viewsonic, it doesn't matter. Most of them are 6 bit.
They are cheaper, and they have faster response times.
8-bit LCD panels are almost a niche specialty 'pro product' in today's market, and unless you went out of your way to buy an 8 bit screen odds are you took home a 6-bit TN panel, advertised as showing "16.2 million colours" without even knowing it.
Its not just Apple. Although they seem to have gone beyond marketing deceptiveness to outright lies and deserve to be taken to task about it.
But don't for a minute think all those free Dell monitors bundled with low end PCs are anything better. Hell, even the ones you can pay to upgrade to aren't often anything better than 6-bit.
I realize that. I was responding specifically to the inaccuracy in the parent post.
Incidentally a guy (Mac user) on our forums ran some tests on his Thinkpad and found that it does indeed have an IPS display. So although TN screens may be common on laptops they're not ubiquitous.IBM made several ThinkPads with IPS panels 2-4 years ago, although none were produced in large numbers. The 14" and 15" IPS screens are no longer being made. The only one I know of still being sold is the X-series tablet, which has a 1440x900 12" IPS screen that I believe is also now out of production.
TN was just too big and cheap for IPS to survive. There was no money for the panel makers in producing a tiny quantity of $100 more expensive laptop screens for the few buyers with enough basic perceptivity to tell the difference.
Actually, there were two 6-bit modes on the Amiga - EHB, as described, and HAM (Hold And Modify), which caused the pixels defined as colors 32-63 to be defined as "the color of the pixel to the left, but with its (R|G|B) value replaced with ...", thus allowing for all 4096 colors on-screen at once, but usually with a slight fudge-factor, depending on your image and how you arranged your 32-color palette.
And that's not getting into the later chipsets, which mostly just added bits... (:
Let's start with, it's multiplicative, not additive. That's 255^3, not 255*3. This is because, as you mentition later, the eye combines all three subpixels into a new color.
If you interpert color as a wavelenght of light as opposed to relative excitment of the three colored cones in your eye, then yes. But no one thinks of that definition. Instead, the obvious usage is 'colors preceived'. Even when you talk about color of a pure wavelength, you can only interpert it as combinations of your three cones.
So, even if one were to concede all your points, these aren't really 1920x1280x24 displays are they then. Because that 1920x1280 resolution has to get shortchanged for the dithering. So you can say that Apple lied about the resolution instead of the color if you like, but it's awful pedantic.
I know people who paid a lot more to get a camera with a Foveon sensor, actually. While I might be unable to notice the quality, they (and their clients) can. And you better believe they would be pissed if they ended up with a Bayer filter instead.
If you want to say that the difference is small, and unnoticible to most people, so that is the optimal thing to make, fine. I respect that, and agree with you. But this is flagrant false advertising. A 1920x1280x24 screen was advertised and not delivered. Bitch about Apple's behavior just like any other major company's.
Your ad here. Ask me how!
Try the following exercise:
1. Find a new 20" iMac (or laptop, or other machine with a crap TN panel). Find a good IPS panel such as the one on a 24" iMac. Put them side by side.
2. Open your favorite image editor.
3. Create a diagonal gradient starting with black and ending with 50% pure blue or green
4. The hard part: tell me with a straight face that you can't see the dithering.
At typical viewing distances, subpixels are small enough to dither with reasonable effectiveness. Full pixels aren't, at least where the color transitions are subtle.
Thanks for the clarification. I was sitting here and thinking to myself, "That can't bee right. 6-bits of color is how much my RGB Amiga 500 used in 1987 (64 colors)."
No offense intended, but I can't believe in this day and age that people who are otherwise generally well-versed in computers and computer peripherals are still not even aware of this specification for LCD screens - which is probably the most important one.
Everybody gets so fixated on response times and viewing angles, but none of that amounts to a hill of beans without color rendition and accuracy. The most important specs to look at on any LCD screen are bits per pixel and gamut. Contrast is also useful to know if you also know black level threshold. Without that, though, contrast ratio is useless because it's much easier to make an LCD screen brighter than it is to make one darker, and LCD screens these days are by and large capable of much more brightness than would ever be usable. A contrast ratio of 10,000:1 is meaningless without knowing the starting point for that range.
Unfortunately, most manufacturers make the specs that are actually important almost impossible to find. Even a lot of manufacturers who could brag about these things - because their screens do all the right things in color rendition and accuracy - choose not to. Dell, for example, is probably the largest manufacturer of 8bpp Super-IPS screens with wide color gamuts. Their higher-end screens, which are still pretty cheap relative to most screens marketed towards professionals, are among the more capable out there. But I have never seen Dell actually try to make this argument - I have never seen them argue that colors on their monitors are more vibrant and true-to-life (to use the marketing-speak that they'd probably go with), even though they could.
The reason is that people don't seem to know or care. And they should. You're looking at a screen in some cases almost every waking hour you have (if you're like me and work on computers, then go home and switch on your laptop), and many people are using them for things like photo editing or home video production. People should be demanding good color rendition.
It's almost shocking that Apple, of all companies, does not provide 8bpp panels across their entire line. At the very least, given their reputation as a manufacturer of computers for creative professionals, they should be making it clear which screens are 8bpp panels and which ones aren't. And they should be publishing their screens' gamut as well.