About the human perception part, it always bothers me that two humans who see a certain color might call it the same color (let's say "yellow"), but can be perceiving completely different things in their brain. And we have no way to know for sure.
Color is also cultural. In russian, there are separate words for light blue and dark blue, so I am more attuned to it than others who just see it as blue.
Apparently men and women see the color red differently!