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Is the 4th Yellow Pixel of Sharp Quattron Hype?
Nom du Keyboard writes "Sharp Aquos brand televisions are making a big deal about their Quattron technology of adding a 4th yellow pixel to their RGB sets. While you can read a glowing review of it here, the engineer in me is skeptical because of how all the source material for this set is produced in 3-color RGB. I also know how just making a picture brighter and saturating the colors a bit can make it more appealing to many viewers over a more accurate rendition – so much for side-by-side comparisons. And I laugh at how you are supposed to see the advantages of 4-color technology in ads on your 3-color sets at home as you watch their commercials. It sounds more like hype to extract a higher profit margin than the next great advance in home television. So is it real?"
http://en.wikipedia.org/wiki/Opponent_process
"Kill 'em all and let Root sort 'em out"
Representing yellow with a mix of green and red is already a hack. What's wrong with software determining that the color of a pixel is yellow and actually lighting up a yellow light?
Maybe a yellow light looks more convincing than a red and green light right next to each other. I'd want to see for myself before making blanket judgments.
joking aside... some of the newer TVs with LED backlighting actually do something like this... Lighting up the picture with thousands(ish?) of independent LEDs (as opposed to a couple of souped up flourescent tubes) means they can selectively dim or turn off entirely sections of the backlighting. So when large parts of the scene are dirk, large parts of the backlighting is dimmed as well, thus increasing the contrast. It also saves a bit of power, making it easier for them to meet energy star standards, etc...
Parent is correct. Any colours around green and cyan are usually terribly unsaturated on most monitors. In fact, even in 'real life', it isn't theoretically possible to experience true cyan/aqua because the nearest direct wavelength will stimulate the red eye cone to some extent creating colour pollution.
There is a trick around this, which can be found by over-saturating the red cone. This weakens it temporarily, and then when shortly afterwards you see anything resembling cyan, it will appear as close to the true qualia as you could ever expect. The "Eclipse of Mars" illusion that follows in the below link demonstrates this for those who are curious:
http://www.skytopia.com/project/illusion/2illusion.html
Why OpalCalc is the best Windows calc
Back in the 1960s there was an ad that did some trick that caused a black-and-white television to display what the eye perceived as colour. There was an explanation as to how it was achieved but lo these many decades later I have no recollection what it was (nor what the ad was for, either). If I hadn't seen it myself, I'd not believe it could be done.
~REZ~ #43301. Who'd fake being me anyway?
A lot of TV sets that use local dimming have a big problem showing starfields. The average color in a starfield is pretty dark, so the LED goes dim and not bright enough to show the stars. It really takes the punch out of Star Wars Special^n Edition if you can't see the stars.
That's my point though. How can a apx 515nm wavelength be a fully saturated green if the L cone is also being activated to some degree? That would be the extra pollution I'm talking about. I believe a much purer green would result if you somehow disabled the L cone. Unless you think we might see a more cyan/blue-like hue here?
To get a definitive answer, I would be interested to see what one would experience if you disabled two of the three S/M/L cones. I'm suspecting you would see pure red (disable S+M), green (disable S+L) and blue (M+L). Any research into that?
That's interesting, but it isn't "green"
What is it then?
Why OpalCalc is the best Windows calc
and so it does.
http://en.wikipedia.org/wiki/Imaginary_color
Neat snippet from the article:
"At Walt Disney World, Kodak engineered Epcot's pavement to be a certain hue of pink so that the grass would look greener through the reverse of this effect."
Sneaky!
True, but the regular LCD color gamut is smaller than the sRGB/Rec 709 gamut that is encoded in the HDTV video standard.
Basically, LCD panels use relatively wide spectrum color filters, so that they don't loos too much light in absorption. The result is a relatively small gamut - smaller than plasma or CRT.
That's my point though. How can a apx 515nm wavelength be a fully saturated green if the L cone is also being activated to some degree?
Because all light of a single wavelength is automatically "pure"; it doesn't matter what your cone responses are. The cone responses are just a code to transmit that information to your brain. Your cone responses are such that they overlap (for good reason), but that doesn't keep you from seeing pure colors.
And actually, you perceive color contrast anyway, not absolute RGB values or wavelengths. So, even if you get a group of cones to produce a pure "green" response somehow, that will simply be processed as being part of a strong red/green contrast and result just in a vivid green percept.
Admittedly one of the problems here is that adding a fourth channel would require a 4-dimensional color space to fully utilize that extra channel. To really utilize this sort of new feature would require a whole new image recording system.
One of the problems facing would-be extensions of the color gamut like adding another color is in part an unlearning of what it means to make a color. In reality, a given color that you see from an object is made up of an entire spectrum from near infrared to ultraviolet (UV-A, to define a "color"), and is a wave function of all possible frequencies along that spectrum.
Somewhere along the way some crude but generally effective simplifications of this philosophy have resulted in things like the YUV and RBG systems, but it should be noted those are 3-dimensional color spaces. Note that the word "dimension" is not in reference to lengths here, but rather representations of the color. Each dimension is merely one more piece of information to display that color.
So whenever you use a 3-dimensional color space, you are reproducing that color spectrum wave function by only selecting three frequencies out of the whole spectrum with which to "broadcast" that information... and you are discarding quite a bit of additional information along the way. This is why color reproduction is quite difficult, and never really gets it "right" in most cases. Try as you might, no possible method of reproducing a color where the information has been discarded can be recreated. Heck, that is basic information theory here too.
Some may counter that a human eye perceives only three colors anyway. Well, that isn't quite true, as there are people with sensitivity to more than three colors (tetra-chromaticity) and of course people who only perceive effectively two or even one color ("color blindness"). Even with all that, not all people perceive the same colors either in the same way, so what may look "good" to one person may look "awful" to somebody else. What it all boils down to is that to really do a proper representation of the color, it really is vitally important to completely and accurately reproduce that entire wave function which represents all possible frequencies.
Think of it more this way, perhaps. Imagine if you were listening to some music, but the recording medium only reproduced the songs with three frequencies for playback. It would be some rather boring music. BTW, it is possible to "sample" light in the same manner that sound is sampled to give a more accurate reproduction of a color, but that would be an insane amount of data as the sampling frequency would have to be on the same order as the frequency of the light.... actually a higher rate of sampling to be precise.
One of the really nice things about light from an incandescent light bulb is that it is spread out over nearly the entire frequency spectrum. Traditional film projectors take advantage of that fact and when color film is shown in front of that light bulb, the frequency spread of various color layers on the film tend to smooth out with each other and generate that continuous spectrum. It still isn't perfect and color film still has only three channels (usually) but at least an attempt to re-create that whole frequency spectrum is there. Also note that different film manufacturers have a frequency response that is sometimes different, which is why some film manufacturers are preferred over others and certainly impacts the film making process in some subtle but interesting ways.
For LCD screens and worse yet for LED systems, the frequency curve isn't nearly so good. If you would look at it with a diffraction grating or prism that separates the colors out, you would see some sharp lines rather than a continuous spectrum. That is where the real problem lies with LCD panels and why color accuracy is not very good. Certainly adding a yellow line to that curve would generally help to smooth out that spectrum or at least add some more visual information, even if that color information isn't being directly recorded by the storage medium.