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Actual violet (like UV LED or mercury lamp) should stimulate almost exclusively S cones. But it turns out that if you take blue, which stimulates M and L more t
by qb45 11y ago
Actual violet (like UV LED or mercury lamp) should stimulate almost exclusively S cones. But it turns out that if you take blue, which stimulates M and L more than violet, and then add even more L stimulation, you end up with something that "feels" more violet than blue (at least to me). This is what bothers me. It looks like two distinct inputs producing the same output, even though there exists an intermediate input which produces different output.
- Someone 11y agoTwo distinct inputs producing the same output is metamery. https://en.m.wikipedia.org/wiki/Metamerism_(color) https://en.m.wikipedia.org/wiki/Metamerism_(color). Without it, color printing and color televisions would be way harder to create.
- qb45 11y agoYou aren't paying attention, by "inputs" I meant "inputs from retina to the nervous system", not "inputs to the eye". Most metamerism can be trivially explained by different combinations of light stimulating cones in the same way. But it looks like red+blue and violet are different and there is just no reason for them to be perceived the same, except that apparently there is also no reason to distinguish between them.
- Someone 11y agoThe sensitivity of the red cones appears to go up near violet (http://www.yorku.ca/eye/specsens.htm http://www.yorku.ca/eye/specsens.htm) Wikipedia claims that is because of "a second resonancy of the red-sensitive cone cells." (https://en.m.wikipedia.org/wiki/Violet_light https://en.m.wikipedia.org/wiki/Violet_light)
- qb45 11y agoWell, this finally makes sense. None of the red cone sensitivity plots I've seen previously showed secondary peak, but that's because they were always cut somewhere in the blue region.