The simplest way to make dark brown is to mix orange with a little black. To control the shade, mix white or black into the mixture.
Mixing colors to make brown offers more variety. Brown is a tertiary color. This means that brown is made by mixing a primary color with a secondary color. Brown can be created by mixing orange with a little blue. Brown can also be created by mixing red and green. This does not mean that brown cannot be made from other color combinations. Mixing all three of the primary colors will make brown. For example, mixing a red and blue that contains yellow also produces brown.