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

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

What the primary pigments do is *remove* one of the red/green/blue colors from white light, while allowing the two others to remain. Magenta is opposite green, cyan opposite red, and yellow opposite blue. If you combine two of these at full strength, you only allow one of the primary lights: for instance, mixing magenta and cyan gives a blue color. (The reverse also holds true—if you combine red and blue light, you get a magenta color, and so on.) A fourth black pigment is sometimes added to reduce how much of the other pigments are needed for dark colors.