What are the properties of Red/Green/Blue that make them the primary colors for light? Are they the only set of three colors that could combine to make all other colors?

Question

And I have the same question for pigment primary colors (magenta/cyan/yellow).

In: Physics

Answer 1

Human eyes have 2 types of light-sensitive cells. Rods distinguish lightness and darkness, while Cones distinguish color. About 95% of people have 3 types of cones each tuned to a wavelength of visible light. (Colorblind people have faulty cone cells so one or more wavelengths is not picked up by the brain.) In a normal eye one type of cone picks up red wavelength, one type green, and one type picks up blue. When red and green cones are activated it creates the image of colors between those two wavelengths, like oranges and yellows.

So in light-mixing, red-green-blue is the least amount of colors needed to create all other visible colors/hues, since the human eye can only detect these three, due to only three types of light-sensitive cells.