In the theory of everything section of the MKaku forum, I asked Nereid about the physiology of color, especially the bands detected by the cones, and she responded as follows: Some sources for colours and bands, in general (probably gives you more than what you asked for) : http://www.photo.net/photo/edscott/vis00010.htm [Broken] http://ergo.human.cornell.edu/stude...pdfs/vision.pdf [Broken] http://www.yorku.ca/eye/specsens.htm Here's one article on the sex differences (looks like some women may have 5 different types of cones - blue, two green, and two red): http://teachpsych.lemoyne.edu/teach...olor_vision.htm [Broken] How does this happen? The genes for cones are on the X chromosome, and women have two. What if the expression of a red cone in one cone is different from the expression of that in a neighbouring red cone? Since theory of everything is inappropriate for a discussion on this topic, I am starting this thread here. I think we can take it as given that Nereid's links pretty well cover the subject of the cones, their spectral range, and the connection to genetics. What I would hope to see here is discussion of the neurophysiolgy of color processing in the brain, particularly how the color sense is created - how does the merged info from the cones get built into a unitary sensation?