This document discusses color theory and the use of color. It explains that there are three primary colors - red, yellow and blue - which can be combined to create secondary colors. Colors are arranged on a color wheel. Complementary colors are directly across from each other on the wheel. Warm colors like red, orange and yellow tend to come forward while cool colors like blue and green recede. Color trends are influenced by social, economic and technological changes. Understanding color theory helps designers anticipate client preferences.