RGB to become RGBCMY 521
elgatozorbas writes "The basic color elements of television have not changed much since 1954; a half-century after RCA introduced the first color set, the RGB (red, green and blue) system used then still prevails. But Israeli company Genoa Color Technologies has broken the RGB barrier by adding one to three primary colors such as yellow, cyan and magenta, thus expanding - from 55 to 95 percent - the coverage of the visible color gamut. The promised result of this multi-primary color (MPC) technology is a television picture that, with its truer, more vibrant color and brighter image, looks more like cinema than video. Also covered in IEEE Spectrum."
MPC: possibly the next standard? (Score:5, Interesting)
Re:MPC: possibly the next standard? (Score:5, Insightful)
Re:MPC: possibly the next standard? (Score:2, Funny)
Re:MPC: possibly the next standard? (Score:5, Funny)
Re:MPC: possibly the next standard? (Score:5, Informative)
Since they are supposedly coming out with sets later this year, I would probably wait myself if I were about to drop a couple grand on a new set and get a look at the technology in the show room.
Maybe it's because we're spoiled with the high resolution of computer monitors, but I can barely stand to watch normal TV, even the majority of the newer plasma/LCD TVs have horrible images. There's a lot of room for improvement. The best ones I've seen in my opinion are DLP rear projection sets, but then I haven't really kept up with it the last year or so, so there might be better looking stuff out there now.
Re:MPC: possibly the next standard? (Score:5, Informative)
Not to be a nag, but that's not what a comb filter does, bud. It seperates the Luminance from the Chrominance in an analog TV signal. When viewed on an oscilloscope, the peaks of each alternate with each other, giving the appearance of a comb.
New standard still necessary (Score:4, Interesting)
And here's what you said: "This isn't a new standard, it's just an after effect applied to existing signals."
While you're right that it can be used in transitional technology, you're wrong that it's "just" an after effect. Nobody would say that Technicolorized B&W reproductions are the same as actual full-color originals. And here, you're going to need a format that preserves color information in the new 5 color system if you're going to exploit the real improvements in this color technology: closer reproductions of actual color.
Re:New standard still necessary (Score:5, Interesting)
CMY are really "combinations" of R G and B.
So, what's happening is that they are tossing in "intermediate" colors in roughly the same way as a 6 or 7 color printer. The exact equations are probably proprietary, but the process is pretty standard.
This comes in to play at two places. First, HDTV has a pretty ambitious color gamut, so videos designed around the HDTV gamut will look better, assuming of course that the source footage is equally high quality.
Second, there are colors that your eye can perceive that are not representable by the RGB system.
Overall, the research is already done. There's actually quite a few different ways to represent this data. PhotoCDs already use it. You want to use L*a*b or XYZ or one of the other CIE color systems.
I think it's interesting, but when I read the headline, my first thought was "Gee. What took them so long?"
Re:New standard still necessary (Score:5, Interesting)
This is false. C, Y, and M are different wavelengths of light from R, G, and B. Because the human eye only has receptors for R, G, and B, we can't distinguish between equal quantities of R and G and a single wavelength in between the two, namely Y. In other words, we are able to trick the eye into perceiving a full color spectrum using only three different wavelengths of light.
Re:New standard still necessary (Score:5, Funny)
Mantis shrimp [berkeley.edu] have at least eleven different receptors, and lots of birds and fish have four or five. So I guess it's the logical direction to go once the human market for RGB monitors reaches saturation.
Re:New standard still necessary (Score:5, Informative)
They are on your standard RGB monitor, but not in the general case. For example, take a look at the CIE "Tongue" chart displayed e.g. here [virginia.edu]. With you monitor, you can only display colors in the red, green, blue triangle, but one could add pure cyan at 490nm and actually increase the area/gamut.
Second, there are colors that your eye can perceive that are not representable by the RGB system.
That would be the good old RCA, phosphor based RGB system. If you ran your display with e.g. lasers with 410, 520 and 700nm respectively, you could get a gamut that's almost indistinguishable from the full gamut the average eye can percieve. The smaller area covered in the green region on top of the chart would probably be neglegible due to the decreased capability of the eye to distinguish between greens. So, not RGB is the problem, but the technology to record and display it.
Re:New standard still necessary (Score:3, Insightful)
I think the first thing to spring to graphic artists' minds is 'when can I get a monitor like this?' And also, how much of a strain would it be for a video card to compu
Re:New standard still necessary (Score:5, Interesting)
I had never tried to think outside the RGB world because it 'technically' displays all colors, though it struck me that the colors in-between RGB will come out dimmer than they should.
No, RGB technically displays more discrete colors than our eye can see. That does not mean it "displays all colors." There are some colors RGB displays that we cannot distinguish between, and there are some colors we can distinguish that RGB cannot display.
Re:New standard still necessary (Score:5, Informative)
Absolutely not true.
For people with normal color vision, in addition to the "rod" pigment (which is not a significant player in color perception and daylight central vision) there are three color receptor pigments located in the "cone" cells, which have broad reception peaks with well-known shapes. The response of those three sets of cells to an image can be accurately modeled by using three sets of sensors and filters that model the three pigments' frequency response.
The problem comes when, given this measurement, you try to stimulate a viewer's cone cells to produce the response equivalent to the light you measured. If you just pick three color phosphors at the peak of the three dyes' response curves, you find that the colors don't stimulate JUST the cones you intended. The green light, for instance, will strongly stimulate the green-responsive cones. But it will also weakly stimulate the red and blue cones. Similarly, red light will strongly stimulate red cones, weakly stimulate green cones, and very weakly stimulate blue cones. Ditto the other way around with blue light.
This has two effects:
First: Even within the range of combinations of stimulus the three light sources can produce, simply playing back the signal will cause the results to be somewhat more pastel than the orignal scene. This can be compensated for to some extent - by subtracting out appropriate amounts of each color's signal from the signals going to the others color emitters.
Second: You can't make the emitters emit a negative amount of light. The result is that there are scene colors, saturated and nearly-saturated colors between the phosphor colors you chose for reproduction, that can produce color sensations that these three screen colors can't reproduce. These scene colors will ALWAYS apper somewhat washed-out if you only reproduce the image with three screen colors.
So with three values you can accurately transmit any color a normal eye can see. But with three phosphors you can't make the eye see some of these colors.
The two-dimensional representation of the relative responses of the three dies looks something like a spearment leaf with the base sliced off. (See figure 12 of this [virginia.edu] web page. And thank you, canavan [slashdot.org]) The edge of the leaf represents the response to a pure spectral color, and regions within it to mixes of colors. If you try to reproduce the response with three phosphor colors, you are picking three points on the leaf edge and drawing a triangle between them. By adjusting the relative amounts of light from the three phosphors you can produce a stimulus corresponding to any point WITHIN the triangle. But you can't produce one corresponding to the arcs of the leaf that are outside the triangle.
But by picking more points along the leaf edge you can draw a polygon and hit any point within it. This covers more of the leaf and leaves fewer colors missing. (Indeed, just a couple extra points can give you most of the leaf.)
You still send the signal with the three values corresponding to the response you want from the eye. But now your monitor processes it into more than three colors to put on the screen, to get the eye to respond more closely to the response it would have had to the original scene.
(Note that people with some forms of color blindness have cones with pigments that have abnormal frequency responses. Such people will not see a color TV image as right even with this upgrade, because the camera will not have correctly encoded what THEIR eyes would have seen. They need a camera with a different response, and yet another set of phosphors in the monitor, to get a good match.)
Re:MPC: possibly the next standard? (Score:2)
Re:MPC: possibly the next standard? Um.Nooooo.... (Score:4, Insightful)
First of all it's not a new idea - we looked into it at apple in the mid 80's as a way of getting more brightness out of LCDs. Using a CMYG pattern for example.
Second, a cursory glance at the CIE diagram [gsu.edu] teaches those who understand how it works that well placed RGB primaries cover almost the entire visible gamut (90% or so). There just isn't 20% left to add with a few more primaries, let alone 65%. That's not how vision works. (A cyan primary might add about 10%, but a yellow doesn't do much of anything and magenta just isn't a primary).
And third, neither video nor movies are color matched anyway. There's no "right" color for a tv program. It's what you want it to be. That's why NTSC stands for Never Twice the Same Color. Expanding the gamut is just like turning up the saturation on your TV. Is your saturation maxed? If so, you'd probably like a TV with a larger gamut (OK, it's not quite that simple, but video programming is targeted to the typical gamut of a TV, so the new technologies typically have to be turned down or they look a unnatural, as the article described. That is, if you really use the new gamut, it looks borked anyway, unless you like that sort of thing.)
If you've got crappy, unsaturated primaries, then adding more colors can expand the range, but at the expense of monumental complexity in the color math. Comon - getting color matching to work even marginally right with only three primaries is a task yet to be even partially achieved - how many of you have color calibrated monitors? And you want to add more primaries? Get a grip on the 3 you've got!
The press release does speak of a truth in subtractive color displays (like LCDs but not CRTs) that there is an intrinsic trade off between color purity (gamut) and brightness. Of course you can always use a brighter lightbulb/backlight... Or an alternative primary color technology like CRTs LEDs OLEDs Lasers... etc today. Large screen OLEDS would have a far better gamut than this crap anyway.
If you want to see amazing color look to laser displays or Sony's new reflective ribbon technology (that uses a laser as the source) with pure RGB primaries, there's no advantage to be had...
As for the technology being unique or special (not short bus special, though it is that) it's not. Your 5/6/7/etc. color inkjet printer does exactly the same thing. With reflective images (subtractive color) you don't really have primaries, you've got inks, and long ago people chose to print in RGB complement CMY (the K part is just because most inks suck and CMY all togehter would be grey, not black, so they added the black - sound familiar to the story? That's only about 100 years old). Anyway, looking back at our old CIE diagram we see that Cyan Magenta and Yellow inscribe a wee triangle even with fully saturated inks, so Epson chose to add a few more colors (and then more, and more) and figure out the color math behind the transformation from CRT RGB primaries (or CIE LAB) to CMYKC2Y2M2 etc. It works well with printers (Epson was actually copying Pantone's Hexachrome offset process, which itself is probably not the first).
It's an OK idea to improve the image quality of the color mixing functions used to filter incoming light for color cameras (typicaly CMYG, though some cameras now use RGB), but it's just silly with LCDs. If you're really a color fanatic you're probably using a CRT anyway.
As an aside, in the persuit of some research about 10 years ago I found a paper article presenting research in capturing archival images of paintings and other works of art, and seeking to eliminate all possible metamerism between the color mixing functions of the detector and the human visual system. The authors found that to do so required a 7 primary system. I haven't been able to find the article again and I'm not
Re:Smoke and mirrors (Score:5, Insightful)
Having to "make up" the additional color data is just a temporary measure until content creation software and image acquisition hardware catches up to the gamuts possible with these new monitors.
I, for one, welcome our new RGBCMY masters.
This will be great for Tetrachromats (Score:5, Interesting)
You are a tetrachromat! (Score:5, Informative)
Most folks don't realize, but there really are four primary colors. Most geeky types are familiar with the red, green, and blue cone cells in our eyes -- but the rod cells that are used for night vision have their own separate response spectrum, weighted heavily toward the blue/violet end of the spectrum.
That means you have four separate "detector systems" in your eye, each of which is sensitive to a different slice of the optical spectrum. In particular, you can distinguish shades of violet and magenta that differ only in the blue-cone/rod response levels.
Ever think about why blue light is used universally to signify "darkness" or "moonlight" on stage? It's because, in low light levels, your cones shut down and your rods -- which in bright light connote blueness -- are the only part of your retina that works well.
It's also the reason why night-vision flashlights are red, and why blue LEDs appear so bright when used as flashlights. The red light doesn't stimulate your rods, preserving their sensitivity; and the blue light gives you extra rod stimulation per unit power, making blue LEDS very efficient as nighttime illumination.
Re:You are a tetrachromat! (Score:5, Informative)
Re:You are a tetrachromat! (Score:4, Informative)
Incidentally, it's also why the sky is blue during the day and orange/red at sunrise and sunset. When the sun is overhead, blue light gets scattered in the atmosphere, giving the whole sky a blue look. When the sun is near the horizon, there's a greater thickness of air between it and you, which scatters all the blue light away (toward the part of the Earth where the sun is overhead, and some back into space).
Re:You are a tetrachromat! (Score:5, Funny)
Re:You are a tetrachromat! (Score:4, Informative)
Now to deal with the *reason* you ask the question. RGB is no more or less valid a representation of color than is YCbCr. They are merely different models of color space. (Think of each of the elements -- [R,G,B]:[Y,Cb,Cr] -- as an axis in 3D space.) Both models represent hue, but each places a particular color at a different place. So your real question is why we would ever want to deal in YCbCr when our eyes work on RGB principles.
For one thing, it's much easier to compress YCbCr color space than RGB color space. Because the eye is much more sensitive to changes in Y than in Chrome, we can actually throw away every other row and column of Chrome data and interpolate it when uncompressing.
To illustrate:
Imagine a 100x100 pixel image. This is 10000 pixels and, assuming 1 byte per RGB color channel, 30000 bytes of image data -- 10000 bytes per color.
Now, if we transform the RGB color space into YCbCr, we end up with 10000 bytes of Luminosity, and 10000 bytes each of Red and Blue color data.
So what's the advantage? As I said, the eye is very sensitive to changes is Y and much less sensitive to changes in color. We can take advantage of this by simply discarding some (or most) of the color data in the first stage of compression. If we only throw away 50% (say, every other row or every other column) of the color then we effectively cut two thirds of our data in half!
In practice, it doesn't hurt much to be very aggressive and remove 75% of the color (for example, remove every other row AND column), turning the 20000 bytes of color data into 5000 bytes. The resulting YCbCr data is now 15000 bytes, or half of the original, before any other compression methods have been applied.
To reconstitute the image, we merely interpolate missing color pixels and apply the "fuzzy" color data over the crisp luminosity data. Transform back to RGB color space and, for most natural images, our eyes can't perceive the difference.
This is, I believe, roughly how JPEG works. And now you understand why JPEG is called "Lossy."
Re:This will be great for Tetrachromats (Score:5, Interesting)
She said, Thats ruby, i meant the red one.
So i handed her one of the other red ones.
No, thats rose,
On and on this goes, and then i finally tell her to pick the damn red shirt herself, she goes into the closet, takes a look at the 12 "red" shirts she has, and says, "see the red one, stupid". From what my buddies tell me, this is a very common issue, and perhaps these women have been overlooked for so long is that most of the doctors are men, and they just think the women are crazy. (My GF informs me that its really the other way around, we simple men are just blind!)
Re:This will be great for Tetrachromats (Score:5, Funny)
Re:This will be great for Tetrachromats (Score:5, Funny)
"Hand me my grey shirt."
"You mean the greyish-blue one or the greenish-grey one?"
*sigh* "70809E, Honey!"
"Ok, thanks!"
Re:This will be great for Tetrachromats (Score:5, Funny)
Biologically speaking, how... (Score:4, Interesting)
Re:Biologically speaking, how... (Score:5, Informative)
Also, each of the three colors commonly used (rgb) are artificially dark, with each one blocking about 2/3 of the light (since the only let that one color through). So if you think about it, your "white" background is really not as bright as it could be. Some DLP [dlp.com] projectors I think use red, green, blue, and white to get some of this contrast back. But I think these guys have a more interesting idea. Your cyan pixel, letting through both blue and green light, would be brighter than either your plain blue or plain green or blue&green next to each other.
Re:Biologically speaking, how... (Score:3, Insightful)
No that's not for contrast, that's for peak brightness. Since all colors those devices can generate are linear interpolations of the filtered colors, all you can get with white thrown in is bright, non-saturated colors.
Your cyan pixel, letting through both blue and green light, would be brighter than either your plain blue or plain green or blue&green next to each other.
But you couldn't make all things
there's primary then there's primary (Score:5, Informative)
Re:Biologically speaking, how... (Score:5, Interesting)
The stuff above is fact, the rest of this post is my pointless, unscientific, meandering hypothesis:
Obviously we use this concept with RGB signals to create colors like yellow, by tickling both the red and green cones at once with neighboring phosphors, but since the two colors are coming from very very slightly different places, the brain is not necessarily satisfied that it really is the color yellow. Basically, the more spectrum we can cover natively, the less chance there will be of someone's brain mumbling "that color doesn't seem... right"
Re:Biologically speaking, how... (Score:4, Interesting)
The real issue is that, since the curves overlap, the green phosphor triggers the red cone to a certain extent, so green plus blue is cyan plus a bit of red, or a bit less cyan plus a bit of white. So the most pure cyan you can trigger in the eye with an RGB screen is less pure than the most pure cyan you get find in the real world. Purple is more of a mess (since the brain is actually making up colors for combinations that aren't generated by any pure wavelengths, and faking the idea that red is next to violet). But it all comes down to limits on the saturation of different colors due to not being able to keep from stimulating some cone or other.
Go caving sometime (Score:4, Interesting)
Boy, you can say that again. For anyone who *really* wants to experience this, I suggest you go caving some time. In a deep enough cave that no outside light penetrates. Last weekend myself and a group were out, and we all had different models of headlamps. Now, the cave we were in has 3 interesting things going for it here: very banded & multicoloured rock, lots of ice (again somewhat multicoloured due to how it forms over the centuries), and human artifacts (a fair bit of paint on the walls, general human refuse, etc).
Here's the trick: you're in an area where your eyes have never seen the surroundings in natural light. Effectively, you have no reference point to know what colour things are. Now, I personally have one of the newer LED/incandescent combo headlamps (an amazing combination by the way, and for those with any doubt, 3 white LEDs will provide more than enough light for at least 20' around you - no more trying to focus right in front of your feet
This really didn't happen with things like our clothing or other gear, because my brain "knew" what colour that stuff was, having seen it outside, and it adjusted easily. But the rocks, ice, and *especially* the tagging on the walls - very creepy effect. Things that looked green in one light could be red in another. The ice was fun, because it's actually somewhat brown/yellowish in some layers (dirt, I suspect). But the brain wants to colour it blue-white.
We also had a good game of "guess my eye colour" - many of these people didn't know each other very well. I think we scored less than 50% overall
Re:Biologically speaking, how... (Score:4, Interesting)
Re:Biologically speaking, how... (Score:3, Insightful)
Not really. The thing is, everyone's eyes are different.
As you probably know, our rods respond to the intensity of red, green, and blue light. More specifically, each type of sensor has its peak sensitivity at approximately those colors. Our red sensor responds a little bit to blue light, our blue sensor responds a little to red light, etc.
RGB doesn't cover the visible gamut. At all. (Score:3, Insightful)
Nice, but still shortsighted (Score:5, Interesting)
Re:Nice, but still shortsighted (Score:5, Funny)
Why didn't I think of that? This is huge! It would mean that us cave-dwelling worms will get tans, skin cancer, and cataracts just like everyone else- just by sitting in front of our monitor. Also, we could use the IR radiation to heat our TV dinners so we wouldn't have to keep going back to the oven or microwave to check if its done yet.
I know you're being sarcastic but . . . (Score:4, Interesting)
Re:Nice, but still shortsighted (Score:2)
Re:Nice, but still shortsighted (Score:5, Interesting)
Re:Nice, but still shortsighted (Score:5, Funny)
"So where did you get that sunburn?"
"Too much TV I guess."
Or better yet...
"Oh neat, Jesse James is about to weld something again..." *ZAP!* "...oh fuck, my eyes!"
Re:Nice, but still shortsighted (Score:2)
Re:Nice, but still shortsighted (Score:3, Interesting)
No, our brain does not perceive sounds much below 20Hz or above 25kHz, and our ears are physically incapable of receiving them in the first place, unless it's loud enough of course (in which case you feel it instead). I have never read any convincing evidence to the contrary in any paper that isn't written by either a vested interest, or by someone
Re:Nice, but still shortsighted (Score:3, Interesting)
Frequency A and Frequency B, played together, can cause us to hear an aphysical (not real) signal, (f1 + f2)/2. This is far more common with low frequencies. Thus, a 20-20k recording can miss signals that can create things we hear. Its not common, but it does happen.
There's neither such a thing as an intermediary color nor a primary; CMY are intermediary colors in the RGB vector space. RGB are intermediary colors in the CMY vector space. Since the
Re:Nice, but still shortsighted (Score:3, Interesting)
I don't know about chickens, but many birds (especially those that fly a lot / long distances) also have eyes with a quicker response time than ours. So they see more "frames-per-second" than humans are capable of perceiving, on the level of over 100 distinct images per second. I would im
Colors or Pigments? (Score:2, Interesting)
so now they can project reflected colors, aka pigments? hmmm
Uses existing signal and price is right. (Score:5, Informative)
Cheers,
Erick
Re:Uses existing signal and price is right. (Score:2)
Did I miss something?
Most definitely. This is just like all of the customized MP3 decoders that came out that were supposed to "enrich" the sound by adding in the lost harmonics. They didn't fare so well because, ultimately, it was just a manufactured enhancement, and it can't compete with the real thing. This is like turning your amplifier up to eleven.
Nice try... (Score:2, Funny)
Sometimes (Score:5, Insightful)
When I get one of these... (Score:5, Funny)
Nice product placement (Score:2)
smells a little funny... (Score:5, Informative)
From the spectrum article:
While film used in cinema contains pigments that can create an infinitely large number of color variations, TV sets combine discrete amounts of red, green, and blue light to create a much more limited color range.
This isn't true: color slide film uses three layers, just like monitors do: http://www.imx.nl/photosite/technical/E100G/E100G
He says that in printing it's common to have inkjet devices that use six, seven, or even eight primaries.
There are good reasons printing uses so many primaries, but it's usually to make an evener tone. My consumer-grade printer has the traditional CMYK (cyan magenta yellow blacK), but it also has two additional colors: light-cyan and light-magenta. They chose these lighter colors so make the blending smoother and the ink spots less noticible; it wasn't to increase the gamut. Printers also use spot-color [webopedia.com] to make particular colors (such as a company logo) print without needing to use a halftone. These are all just gimicks to get around the fact that printing isn't continuous tone -- in projectors that are continuous tone, these tricks aren't needed.
Basically, it comes down to eyeballs... if you emulate the response curves that your eye is sensitive to [yorku.ca], then you can't perceptually do any better.
The traditional RGB's and CMY's don't match these curves, so they define a gamut that can be improved on. For example, take this projector's gamut [homestead.com] -- its green is far away from the eye's green, so it can't display the cyans well. But, the color model my company is using for its video product uses a much truer green [convergy.de] so we can cover much more of the gamut.
disclaimer: IANACE (color expert), but my most recent project has been color calibration to precise standards.
Color FAQ (Score:5, Informative)
disclaimer: IANACE (color expert), but my most recent project has been color calibration to precise standards.
Parent has very good info, but if anyone wants additional reading, this guy [poynton.com] is a color expert
Re:smells a little funny... (Score:4, Informative)
Yeah, I'm picking nits, but there is a reason by tricks like RGB color work in the first place.
Screenshots anyone? (Score:5, Funny)
Screenshots? (Score:3, Funny)
oh, wait a minute....
it won't matter much... (Score:2)
Re:it won't matter much... (Score:3, Interesting)
I AM a graphic professional and I was taught before all this reliance on calibrations and color models and the like. We color correct images using actual CMYK data that we read from the image itself. Just because a monitor is calibrated to a given image-setter or "direct-to-plate" doesn't mean anything if you don't know the basics.
I'm talking about printing and the printing industry that has totally fallen in love with Colorsync and it's ilk. Y
Re:it won't matter much... (Score:3, Interesting)
Color Space (Score:3, Interesting)
Re:Color Space (Score:3, Interesting)
This is all well and good! (Score:2)
I for one have given up trying to get Photoshop to display the colours correctly...
And who cares about increasing the colour space, when the networks are forcing everyone onto digital, highly compressed channels, and also making people buy higher resoution sets, which will lead to higher compression, and loss of colour informat
Nonsense! (Score:5, Funny)
Coming soon, a computer for TV! (Score:4, Interesting)
Adding two extra colors to this kind of projection television has little impact on the price tag, says Simon Lewis, vice president of marketing at Genoa. He says the new Philips color-enhanced set, to be available next year, needs only a few additional filters and optical components to create the yellow and cyan light, with no changes to the more costly microprojection chip.
Right. Right when we've got all these plants around the world cranking out inexpensive TV's using LEDS and LCD, some whizzo comes along and says, "Hey, look, a great idea and all you have to do is retool everything, develop some newer technology and keep selling it all at the same pricing you're currently at!"
Perhaps the main challenge in converting a video stream from a three- to a five-primary color system is doing it in real time, says Maureen C. Stone, ...
Yay, now we really will need a computer in every TV! More components - more to go wrong, more power consumption, etc.
"How the algorithm does that, precisely, is a secret well kept by Genoa. "It's part of their intellectual property," Stone says.
Yay, more intellectual property. This should drive prices down.
<curmudgeon>
Why, back in my day we didn't have remote controls and we had a folded playing card stuck beside the tuner knob to keep the picture from doing funny things, and we liked it!
</curmudgeon>
I'm sure it will look lovely, while watching older stuff from the bad old pre RGBCMY days.
"Gilligan!"
I'm like, totally there, dude!
When do I get to see a screenshot? (Score:2)
Still incomplete (Score:2)
Why? (Score:2, Informative)
RGB are Additive Colours. (You add them together to create White)
CMY(K) are Subtractive Colours. (You add them together to get black)
CMYK has been used in the Colour-copier/printer industry for a long time. It depends on using White paper to 'iluminate' the colours that have been added.
RGB + CMYK negate each other. Considering that any combination of RGB can give you any colour, CMYK can't (for example) give you 'floresent' colours {without cheating}.
CRT's use gl
Re:Why? (Score:5, Informative)
CMY(K) are Subtractive Colours. (You add them together to get black)
... RGB + CMYK negate each other.
... while LCD's naturally use a CMYk approach
Hehe! No, this is quite false, quite a number of ways.
First of all, colors of light are additive, colors of pigment are subtractive. This is true regardless of which colors you choose. If you had a monitor using the CYM model, you could not produce red, because monitors, being light emitting devices, are always additive, never subtractive, mixing C and Y would add their lights, not subtract leaving just the G. Because of this, you cannot get a lot of colors. However, you can get white, by adding C, M, and Y together. Since monitors are additive, adding CYM makes white, not black.
The LCDs we use today are light emitting, not light reflecting. Thus, they naturally use an RGB color model. If they did not emit light on their own but only reflected like, like a sheet of paper, then their natural color model would be CYM(K). But that's just not how things work.
Re:Why? (Score:4, Insightful)
Remember: It's about emitting light versus absorbing light.
If you have three flashlights with thin plastic in front, one of cyan, magenta, and yellow... When you combine the beams, things will get brighter (of course... Three flashlights). That's because the method being used to create the light is an additive process.
If it were a subtractive process, then you'd be able to make a "flash dark".
Because printing is always a subtractive process (Paper starts white, and must be made darker), the CMY/K gamut is used. (Notice that these three colors are less "strong" than RGB, making them easier to control and combine for printing). In really advanced printing, you can get multitudes of colors, to reproduce more variations, or to get more accurate color (Because sometimes mixing CYM to get perfect tones isn't as effective as it could be).
Keep in mind: We use combinational color models, because we find them managable and convenient. However, these color models are not perfect, and cannot be. We won't ever have it perfect until we're able to serve up colors by frequency, and have them displayed accurately. Even high-quality film is limited by the chemicals used to make the film.
~D
noooo (Score:3, Insightful)
You wouldn't call a painter "counter-productive" for having red, green or blue paint, would you? Then what's so wrong about a screen having Cyan, Magenta, or Yellow?
See, there's two ways to mix color: adding them (shining multiple light sources upon a surface, or directly at a receptor), or subtracting them (mixing multiple pigments or overlapping m
Correction.... (Score:3, Informative)
As many of you have pointed out, My momma must have dropped me on my head when I was a child.
I was wrong with the statments that I made. I was purely thinking of the "painter" analogy, and not the "flashlight".
Sorry, please feel free to delete this thread.
I am an idiot.
So what!? (Score:3, Insightful)
Tell me you're not in denial - and I won't listen.
4:2:2 and 4:1:1 colour sampling (Score:4, Informative)
I've not seen this mentioned... (Score:3, Interesting)
Various video media may not have the necessary color resolution to drive these displays, but (given quality art assets;) newer video cards do [nvidia.com].
I wonder how these types of displays compare to Iridigm's upcoming products [iridigm.com] on color fidelity. Those look quite interesting, especially at effective 200 DPI.
Why stick to the RGB standard at all? (Score:3, Interesting)
Impossible (Score:3, Interesting)
Indeed, with a number of primary colors (which must lie in the horseshoe shape), one can onl
Larger gamut.. *yawn* (Score:5, Interesting)
Judging from the gamut chart [ieee.org] for this RGBCMY, the boost in color range is primarily in yellows and cyans. Gold, as they note, would be a good application. Cyan.. well, that's mostly skies - and those already appear just fine on TV. A fairly decent increase in magentas/purples as well (when taking the assymetric lobe into account), but again.. not seeing its application much.
Unless following the British royal family (lots of golds and purples) a lot, it doesn't appear to offer all that much. Especially considering movie people butcher things anyway (DVD gives a more stable picture, sure.. at the compromise of mpeg artifacting and even encoding issues.. twitches ever 25 frames are annoying - luckily only a few suffer from this).
On the other hand, a higher dynamic range would be immediately noticeable anywhere.
A sequence with the sun glaring into the camera ?
A car's headlights shining at the camera ?
Highlights on objects ?
Blown-out surfaces from bright lighting ?
All that could then more accurately be represented. And thanks to most things still being shot on film, or already on 10bit CCDs with, formally, underexposure but a gain for the operator, a good bit of extra range is already available in previous and current productions.
Whilst RGBCMY would only really be of use for film (as in, actual film) productions, as digital cameras are in much the same RGB limbo that current displays are.
Wide gamut displays (Score:5, Interesting)
There's a whole bunch of these wide gamut and high dynamic range displays suddenly.
At SIGGRAPH this year, there was a 6-primary (RGBCMY) projection system called IRODORI on display in emerging technologies:
http://www.siggraph.org/s2004/conference/etech/ir
There was also a high dynamic range display (capable of a greater range of brightness) from Sunnybrook Technologies at E-Tech:
http://www.siggraph.org/s2004/conference/etech/hi
And then I saw a few displays on the exhibition floor from NEC with a "WG" specifier for "Wide Gamut". NEC's WG monitor is still RGB but with purer R, G, and B phosphors to obtain a gammut wider than Adobe RGB.
And now there's this one. Way cool.
I can't wait till this becomes more widespread. The question becomes, what will the next color standard be for use in applications and APIs? It doesn't make sense to actually encode color as 6 values for display, since (most) humans only have three kinds of cones. It would make more sense to use something like CIEXYX for color interchange in that case. Especially if we're going to have this wierd mix of HDR and various wide gamut displays around for a while, each which has slightly different needs for color output. Best to just go with a neutral, well-defined intermediate colorspace.
IRODORI six-colorn display at SIGGRAPH (Score:4, Interesting)
Bandwidth (Score:3, Insightful)
Re:Bandwidth (Score:3, Interesting)
1. Loss due to the target color space not being able to represent the color in the source color space; for example RGB cannot represent all colors visible to the human eye (without having negative components);
2. Precision loss in the conversion.
Now these two are very different beasts, and #2 can be avoided to an arbitratry precision if you for some reason wanted to. Actually with some cleverness the conversion could be avoided altogether unt
sRGB can't describe all the colours we can see (Score:3, Interesting)
The problem with RGB is it can't describe all colours the eye can see. This was a problem for the guys that made Salem Cigarettes. The problem is their brand's colour lies outside of the small RGB gamut! The best they can display for their brand in RGB is only an approximization. Sure it is a blue-ish green-ish colour when you see it on TV, but it isn't what you would actually see in reality or with a wide gamut colour device. They weren't the only company with this problem.
This is a huge problem for hundreds of thousands of people every day. There are colours that exist that they can't see in their work. They can sit down on a computer and work in an alternative colour space such as L*a*b* and create these colours and even print these colours, but thanks to our RGB monitors they can't view them! What do they do when they have to print an add for Salem Cigarettes? Guess and check I suppose...
Technically RGB can represent more colours than we give it credit for, you just have to allow for negative values which is only useful mathematically until we invent anti-photons to remove light...
Here is a short link to make explain details:
http://www.cs.sfu.ca/CourseCentral/365/
A few more things I'll add from that course; HVS is basically the worst colour space and CIELAB or L*a*b* is the best. CYMK is technically multiplicitive, not subtractive like so many people like to call it. Our eyes are sensitive to short, medium, and long wavelengths, not Red/Green/Blue. RGB happens to mostly match up with what we percive, but it is an over simplification.
For the real keeners here is a nice FAQ about this:
http://www.poynton.com/notes/colour_and_ga
Re:Isn't the CMY(K) color space smaller? (Score:2, Informative)
2. Film uses CMY
Re:Isn't the CMY(K) color space smaller? (Score:3, Informative)
at least that's my understanding.
Re:Isn't the CMY(K) color space smaller? (Score:2)
Oh, and so far, I don't think anyone has been able to project blackness (the K in CMYK).
RGBCMY is more marketing factoid than it isreality (Score:4, Insightful)
Adding CMY to RGB to create RGBCMY does not buy you anything. Hence, the message starting this discussion thread is misleading.
Why is the television signal so poor in generating an image? The answer is unrelated to RGB. The answer is the the following. Prior to transmission, the analog RGB signal is converted into the digital YCbCr signal. (YCbCr is also an orthogonal set of colors.) Y, luma, is sampled at a reasonable rate, but the sampling system samples Cb and Cr at only half of the sampling rate for Y.
My guess is that RGBCMY is simply a clever attempt to use CMY to restore some of the samples of Cb and Cr that were discarded.
Re:RGBCMY is more marketing factoid than it isreal (Score:5, Informative)
Not true, there are a few colors that are out of gamut [wikipedia.org] on an RGB display.
-jim
Re:RGBCMY is more marketing factoid than it isreal (Score:3, Informative)
Re:RGBCMY is more marketing factoid than it isreal (Score:5, Informative)
That's still a linear combination, but just one that's not particular useful in the real world of phosphors and filters.
Thad
Re:RGBCMY is more marketing factoid than it isreal (Score:3, Informative)
No, this isn't even remotely true. Even if we assume you only meant the visible spectrum, RGB still only covers a small section of it (well, ok, a little more than half of it).
For example, how do you generate a true violet colour of around 400 nm when the blue in RGB is usually 450 nm? It can't be done (well, it can be faked but see below).
For more info about the colour
Not so. RGB, CMY, YUV, etc... are not full gamut. (Score:4, Informative)
For that, you need a more complex model like CIELAB.
Here's some links:
A whole lot of information. [cs.sfu.ca]
Samsung stating that their shiny DTV sets can't match the visible gamut. [samsungusa.com]
A graph of visible, RGB, Pantone, and CMYK gamuts [sheridan.com]
Re:Yellow (Score:2)
Re:Yellow (Score:2)
Re:Yellow (Score:2, Informative)
What you're describing is subtractive color, or pigmentation. When you have no pigments, the canvas is white, when you mix all the colors together, you have black. These are the more familiar primary colors that you learn about in art class.
Re:Yellow (Score:3, Interesting)
You're thinking about combining paints (we all know from school art that blue + yellow = green). However they work in the opposite dire
Re:Yellow (Score:3, Interesting)
It doesn't make that much of a difference, overall. But since everybody's perceptions
Re:Color is not a discrete phenomena! (Score:3, Insightful)
Photoshop experience and an artistic eye can pull out colors to make them more life-like and even treat the other three colors in a hex printing pallet like colors on an oil-based paint pallet, but in reality you can't obtain new information that isn't there un