There is a short but fun post over on Knowing Neurons that looks to be part of a series on color and how color is perceived. Its got some great visuals by the guest author Raz and I can’t wait to see what she has to say about oppositional antagonism.
The National Optical Astronomy Observatory has assembled a high resolution image showing the spectrum of our Sun from 296 to 1300nm. Its interesting to note that visual systems on planet Earth have evolved to detect wavelengths of light given off by our sun and those wavelengths are solar specific. Other stars radiate different wavelengths, but I’d suspect that given the place in the electromagnetic spectrum, rhodopsin or rhodopsin like molecules respond to, organisms evolving on other theoretical planets would likely respond to similar spectra. Notably, while the sun appears to emit light in every color, the most prominent emission appears in yellow-green. This is reflected in the sensitivity of photoreceptors with rhodopsin in the blue green spectrum with a peak around 500nm. Cone opsins also are tuned to this portion of the spectrum with the “blue” cones responding around 420nm and M-cones around 530nm with L-cones around 560nm.
Kate D. L. Umbers has published an interesting manuscript, titled “On the perception, production and function of blue colouration in animals”. Its available for free at the Journal of Zoology here and covers those studies that have proposed a function for blue coloration in the animal kingdom, taking a multi-disciplinary approach before taking you on a discussion of “blue”. What initially grabbed my attention was Table 1. A non-exhaustive list of visual pigments of various taxa showing the wavelengths at which their opsins are maximally sensitive. After that, it was easy to get sucked into the discussion of production of blue, pigmentary and structural blues as well as the crux of the paper which is the functions of blue.
As an aside, if you ever get a chance to see Robert Marc’s lecture on color, do it. Its magnificent. His discussion of the color blue from the physics to the neurobiology is truly wonderful.
Tommy Edison, The Blind Film Critic has been blind since birth. In this sort video from his Youtube Film Channel, he discusses the concept of color to a person who has never before seen. Tommy also has lots of additional videos that give some insight into how the blind navigate through life. For those of us who study vision or are interested in vision, Tommy’s channel is well worth dropping by.