When used for printing purposes, the color black is made by combining cyan (a color halfway between green and blue on the color wheel), magenta and yellow. Cyan, magenta and yellow are created when red, green and blue are subtracted from the color white.
The color black is defined as the absence of light. Using light theory, black is not considered a color because it is formed by a lack of light. If there is no light, there is no color.
When referring to pigments, black is considered a color that is created by combining three primary pigments in equal combinations. In general, the more colors that are combined, the darker the combination becomes.