note pajout Afaik, we know that healthy people have the same chemistry of colour-sensitive cells. I do not know nothing relevant about further signal-processing, I only know that the graphics or other professionals have common, healthy sight. They are just trained to distinguish more colours than we can name :>)<p> But, do not forget <a href="http://en.wikipedia.org/wiki/The_Colour_of_Magic">octarine</a> 738673 738974