>>11511215Considering the leading edge is further from you and the opposite edge is closest (so it pushes air toward you) I'm guessing a Doppler effect.
Technically it's shooting regular white at you but the further away blade edge takes a bit longer, giving the illusion of a stretched wavelength, or at least that's what your eye catches. I bet if the blades were flat there'd be no color spectrum.
What if you stand perpendicular to the blade angle? Does it still doing spectrum?
Also either your eyes or the TV flicker are refreshing at a very close rate to the blade revolution. Blade spins 370° (to a 10° position), refresh frame, another 370° (to the 20° position), refresh frame, etc. So it looks like it's spinning only 10° at a time rather than a full revolution.
I pull these numbers out of my ass, but you get the idea.
