>>14046106Fairly simple, actually.
From dissection and using electron scopes we can see the size of an eye's photoreceptors and, compared to known visual systems (a human's) we can correlate the upper and lower bounds of receptors directly via the size of the receptors.
As receptor size is directly responsible for spectra reception, after measurement it is a matter of simple distance(size of receptor)>frequency(spectrum of light) math.
