Don't want to veer your post too far off track but; what a fine point you brought up about the evolution of the the retina to the sun. I did some study on that a while back because of my graphic work with Pantone/CMYK,RGB,HSL, etc. I found it is a fact that we are now able to actually see more colors than we did even a hundred years ago let a lone 2000. Because my graphic monitor is calibrated regularly I find my self seemingly creating "New" colors (in a loose sense of the term) using the tools in Adobe to create CMYK shades in between the standards of Pantone. It's not these colors weren't there by frequency of reflected light, but to me the key is that elusive feeling that can be evoked by seeing them. Like you said the Yellow of the sun also reflects/evokes that warm and sustaining effect in our psyche. Thanks for sharing your terrific observation prowess!