My new favorite aspect of vision is scotopic vision (actually mesopic vision, the mix between scotopic and photopic vision might be the most interesting). It is really facinating how the specific rod sensitivity is generating a very different value scale than our cones. So blue dots on an orange background looks like dark dots during the day but bright dots at night.
I found the example in a very interesting book: Vision and Art: The Biology of Seeing
It is using visual examples to describe a lot of the stuff that I read about in the scientific papers we use for the algorithm development.