To Mix A Basic Dark Brown Mix equal amounts of Cadmium Red, Cobalt Blue and Zinc Yellow together. This will create the dark brown shown in the top section of the photo above. This is a useful color, but is too dark for many miniatures.
Bittersweet Chocolate Brown To mix a bittersweet chocolate colored brown, useful for dark chocolate in baking or for tiny chocolates, mix one part of primary cadmium red, with one part of the basic dark brown made from equal amounts of all three primaries. If you want to make bittersweet chocolate brown directly, mix two parts of red, with one part of yellow and one part of blue.
Chocolate Brown Chocolate brown appears when you mix one part of the bittersweet brown with one part of zinc yellow. This is the brown color we associate with rich chocolate. To mix it from the primaries, and not from the basic dark brown, you would use one part blue, two parts red and two parts yellow.
Milk Chocolate Brown is made by mixing another part of yellow to the chocolate brown. From the basic primaries this is equivalent to one part blue, two parts red, and three parts yellow.
Caramel Toffee If you mix yet another equal part of yellow to the milk chocolate brown, you will get a deep rich caramel color. From basic primaries this would be one part blue, two parts red, four parts yellow.
Ochre Brown Ochre Brown is a very useful color for miniatures and models, as it can be used for shading baked goods and making browned crusts, and if properly blended can be used to mimic naturally tanned leather for some applications. Ochre brown is mixed by adding two parts of yellow to the caramel brown color. From the basic primaries this means you need 1 part blue, two parts red, and six parts of yellow to make an ochre.
Experiment with your particular clay brand to see which colors you get as you work through a set. As you can see from the colors above, red and blue produce dark intense colors. In the brown ranges you will need far more yellow than either red or blue.