Color vision and X-inactivation.

[hunter]

9. Color vision in the Hominoidea is fiendishly complex.

Our little nocturnal furry mammal ancestors lost the excellent color vision many birds and reptiles still enjoy.

"Trichromacy" in the Superfamily Hominoidea is a wretched evolutionary kludge. It helps me to think of it as "sort-of-good-enough trichromacy."

Further complicating the story, it's recently been discovered that some of the color sorting is done in a structural way, by the shape of optical fibers leading to the light sensitive cells...

Red and green light are funnelled through the (Muller glia) cells, while blue scatters much more

http://www.bbc.com/news/science-environment-31775458

A great deal of color sorting is also done in "software," which means our perception of color isn't at all precise, just a rough guess based on experience and, to put it again in computer terms, some very extreme post-processing which introduces a lot of artifacts into the image we perceive.

The human eye is remarkable in many ways, but it is a terrible camera. What we "see" is a heavily enhanced and "photoshopped" version of the actual reality.