How come red & purple are on opposite, far ends of the electromagnetic spectrum, but when mixing colors together in kindergarten, purple is halfway between red & blue?

Question

Shouldn’t common sense dictate that either both be one, or both be the other?

In: 1934

Answer 1

I think you are mixing up purple and violet, they look similar because that’s how transmission spectrum in conecells works out (red conecells have a secondary sensitivity peak at short wavelengths), but they are not the same. Violet is shortest wavelength visible light. Purple is white light minus green

https://www.pixelsham.com/wp-content/uploads/2016/03/sun_and_vision.jpg

In both cases, long and short cone cells get tickled, medium ones not so much.