Only semi-related, but my favorite fact about colors is how our perception of them is cultural. Like the point where green ends and blue begins can be different based on where you grew up, which is partly why Japanese traffic lights look like what Westerners would call blue. Or that brown doesn't exist on the circuit wheel and is just a particular shade of orange that we have designated to be it's own color. Linguists and anthropologists also found that ancient cultures had less words for colors, which is why the Homeric epics describe the sea as "wine-dark", but gain more over time (apparently the Japanese traffic light thing is also partly related to this).