I was inspired by Liz Elliot’s Magenta Ain’t a Color (via) article to write out my favorite color theory rant: art teachers are lying when they say that red, yellow, and blue are “the primary colors.”
There are two ways that color is created in the real world: in the additive model, used by light-based devices such as your computer monitor, uses red, green, and blue. When all three are combined in full strength, they create white in other combination, they create all the other colors you see on your screen.
The subtractive model comes into play when physical pigments are mixed. The primary colors there are the slightly less familiar cyan, magenta, and yellow. Again, they can be combined to create all the color you see on the printed page of a magazine (actually, the printing process also uses black, because combining the three dyes makes a muddy, unsatisfying black).
What makes these color models so obviously correct is how they interact — combining any two colors from one model creates one of the primary colors of the other model! Check out my graphic above, or open your favorite graphics program and create one for yourself.
So what the heck is “red, yellow, and blue”? It’s a lie, plain and simple. It started when people didn’t know any better, and it’s perpetuated by art teachers everywhere who for some reason believe that it makes color easier to understand than the truth.
It’s a shame, too, since the RGB/CMY color models are strikingly obvious and beautiful, but a little tricky to understand and remember if in the back of your mind you’re tending to revert to RYB. If art teachers could get with the program, we’d have a much easier time understanding how color actually works.