Yellow is one of the primary colors and cannot be made by combining other colors. The other two primary colors are red and blue. All of the other colors are made by mixing two or more of these three primary colors.
Yellow is the color the eye sees when looking at light with wavelengths of 570 to 590 nanometers. The combination of yellow and blue produces the secondary color green, while the combination of yellow and red produces orange. There are many different shades of yellow, all produced by mixing yellow with greater or lesser amounts of other colors. Prehistoric cave dwellers made yellow ochre pigment from clay, and yellow was one of the first colors used in cave paintings.