Red green and blue can't reproduce every color. The three define a limited subset of all possible colors. Adding a fourth color, yellow, will expand the coverage of the color space. Check out wikipedia's entry for "RGB color model" to learn more.
What I'm not sure about is how they will use the yellow, since all the data (in DVDs and whatnot) is stored in RGB.
"A set of primary colors, such as the sRGB primaries, define a color triangle; only colors within this triangle can be reproduced by mixing the primary colors. Colors outside the color triangle are therefore shown here as gray."
@diamondsw "I'm sure some physicists would like to have a word with you.".
Don't be pedantic. The RGB on your monitor can't produce the entire colour gamut. For example, it can't produce proper yellow. That's why the CIELAB colour model uses RGBY and luminance; bigger gamut.
This Sharp TV looks to be using the CIELAB colour model. That's cool.
@diamondsw You're right. I would like to have a word with him...because he's right.
Red green and blue can only show spectral red green and blue. Every other color it produces is non-spectral and is not the same as, say, a laser of that color. So it cannot produce laser yellow. Those three colors produce a convex subset of the CIE color space.
In reality, when you mix red green and blue, you don't create new colors. Its still just a mix of red green and blue. The thing is, the three detectors in your eye respond to certain mixtures very similarly to the way they respond to other spectral colors. That's why R+G looks yellow. However, the actual shape of the CIE set isn't flat on the spectrum curve so no finite number of visible colors can produce the same exact response in the eye as every spectral color just by mixing them. i.e. every spectral color is an extreme point of the CIE convex set.
Physics only knows the colors of the spectrum which doesn't even include pink. Everything else is just your eye interpreting mixtures of those spectral colors.
One should not the irony that in the pictures of the full CIE space you really are seeing redundancies because your RGB computer monitor can't display any colors outside of a certain triangle in it, so is approximates the rest with already used RGB colors.
@garths Why they chose yellow for the fourth is beyond me. Yellow is well approximated. The red yellow part of the space is almost flat. They should have chosen a super saturated spectral cyan-green. That area of the color space gets the least coverage by RGB.
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Why hasn't anyone thought of adding yellow before?
@mellerad
Because every color of light can be made with red, green, and blue. Yellow, for example, can be made by combining red and green light.
@DrTrent
Red green and blue can't reproduce every color. The three define a limited subset of all possible colors. Adding a fourth color, yellow, will expand the coverage of the color space. Check out wikipedia's entry for "RGB color model" to learn more.
What I'm not sure about is how they will use the yellow, since all the data (in DVDs and whatnot) is stored in RGB.
@garths
"Red green and blue can't reproduce every color."
I'm sure some physicists would like to have a word with you.
@diamondsw
"A set of primary colors, such as the sRGB primaries, define a color triangle; only colors within this triangle can be reproduced by mixing the primary colors. Colors outside the color triangle are therefore shown here as gray."
@diamondsw "I'm sure some physicists would like to have a word with you.".
Don't be pedantic. The RGB on your monitor can't produce the entire colour gamut. For example, it can't produce proper yellow. That's why the CIELAB colour model uses RGBY and luminance; bigger gamut.
This Sharp TV looks to be using the CIELAB colour model. That's cool.
@diamondsw You're right. I would like to have a word with him...because he's right.
Red green and blue can only show spectral red green and blue. Every other color it produces is non-spectral and is not the same as, say, a laser of that color. So it cannot produce laser yellow. Those three colors produce a convex subset of the CIE color space.
In reality, when you mix red green and blue, you don't create new colors. Its still just a mix of red green and blue. The thing is, the three detectors in your eye respond to certain mixtures very similarly to the way they respond to other spectral colors. That's why R+G looks yellow. However, the actual shape of the CIE set isn't flat on the spectrum curve so no finite number of visible colors can produce the same exact response in the eye as every spectral color just by mixing them. i.e. every spectral color is an extreme point of the CIE convex set.
Physics only knows the colors of the spectrum which doesn't even include pink. Everything else is just your eye interpreting mixtures of those spectral colors.
There's a lot of good info on wikipedia about RGB and CIE color space. Here's one visualization. http://en.wikipedia.org/wiki/Additive_primaries#Additive_primaries
One should not the irony that in the pictures of the full CIE space you really are seeing redundancies because your RGB computer monitor can't display any colors outside of a certain triangle in it, so is approximates the rest with already used RGB colors.
@garths Why they chose yellow for the fourth is beyond me. Yellow is well approximated. The red yellow part of the space is almost flat. They should have chosen a super saturated spectral cyan-green. That area of the color space gets the least coverage by RGB.
@jedidove
For the same reason Fuji has super saturated yellow film....skin tones.