Artist Must Know How to Mix Primary Colors Together

My first reaction on being asked the question "Why should an artist know how to mix primary colors together?" was "Why wouldn't you want to know?" Isn't curiosity an essential part of creativity, thus discovering what the colors considered fundamental (primary) did when you mixed them would be one of the first things you did?

But a friend I put this to surprised me by saying they didn't associate art with curiosity but rather with imagination. That they thought my habit of "poking things to see how they work" wasn't normal for "an arty type". Oh well, if that's true, then it's another way I'm not normal and I've certainly given up worrying about being that...

Back to the question. I believe an artist ought to know how to mix the primary colors together because color is fundamental to painting and knowledge of how colors interact is therefore crucial. The basics of color theory for painting is that there are three primary colors -- red, blue, yellow -- and that these mix together to create the other colors we know and love (except white and black). Which particular red, blue, or yellow you use changes the outcome of the mixture, as does the proportions you're using. So not only do you need to know what happens when you mix the primaries together, but you need to explore what happens with the different reds, blues, and yellows.

Without a knowledge of what happens when you mix colors you can't begin to explore the technique of glazing, where you move from mixing paint on a palette to mixing it in the eye of the viewer (physical mixing vs optical mixing). And without glazing you can't begin to paint like the Old Masters... so you simply have to be curious about what happens when you mix red and blue and yellow, surely?