Quote:
Originally Posted by geekmaster
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I've learned someting new too. I'd always assumed that the RYB model was a slight misnomer and approximation to CMY. But in fact it is a separate system, just not the most efficient, which is why colour printing uses CMY(K).
The most common* human eye detects red green and blue lightwaves. So additive (e.g. LCD TV screens) use red green and blue pixels.
But when adding pigments to white paper, each pigment absorbs some light and reflects others. Combining pigments reduces the amount of light reflected, as the light that's reflected is only that reflected by both pigments.
Cyan reflects green and blue light, absorbing red
Magenta reflects red and blue light, absorbing green
Yellow reflects red and green light, absorbing blue.
So mixing 100% cyan and magenta absorbs both red and green, leaving just blue reflected light. Similarly for other combinations.
And by varying the percentages of each pigments, it's possible to arrange for the reflection of any proportions of red, green and blue, theoretically allowing full colour printing.
Although there are colour systems that use more -
hexachrome is a case in point, which adds an orange and a green into the mix.
*There are people who don't have the detectors for all three colours, giving rise the various kinds of colour-blindness. Interestingly, there are some people who have four different colour detectors, as there are variants in the genes for the red and green receptors. In at least one person, this has been shown to give enhanced colour vision.