Mixing yellow and purple together results in brown and warm gray, depending on the amount of each color used. Mixing two complementary colors together, such as red and green, blue and orange or yellow and purple, will produce a different shade of brown.
The colors gray and brown are created by mixing all three primary colors in different combinations. Adding white to the mixture will give shades of gray while leaving it out will give a more brownish color. Alternatively, a primary color and its complement can also be mixed. This is because the complementary color is a mixture of the other two primaries. For example, purple is a combination of red and blue. Adding a small amount of purple to yellow can result in ochre, a light brown-gray shade.