Why is it some people need to know exactly what the outcome will be before they try something? What are you going to loose but some time and paint if you mix a red and blue together and don't get the perfect "apple red" or "cherry purple" or "plum"? What might you discover if you mixed every red and blue you had in every possible combination...?
Even if you painting up a color triangle with exactly the same pigments I used, your mixed greens, oranges, and purples will vary according to the proportions of paint you're using. Because you mixed them together more thoroughly. Because you mixed them before you put them on the paper. Because you're using different brands of paint. Because you're using student quality paint. Because seeing what happens is all part of learning color mixing. Because you'll discover all sorts of beautiful and ugly combinations if you mixed every red and blue you have with every other one.
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Comments
Ah, I know what you mean. I personally enjoy the experimentation and seeing for myself what new paints (etc) will do!