To mix a brown you mix a primary with its complementary color, so purple and yellow; blue and orange; or red and green. Browns contain all three primary colors. They're created by mixing either all three primary colors or a primary and secondary color (secondary colors of course being made from two primaries). By varying the proportions of the colors you're mixing, you create the different tertiary colors. What's the Easiest Way to Mix a Brown? Mix a primary color with its complementary color. So add orange to blue, purple to yellow, or green to red. Each of these makes a different brown, so once again make up a color chart to give you a quick reference to refer to.