Color that is mixed in pigment responds differently than in light or optical color mixing. The traditional primary colors, those that are the basis for all others and cannot be made from mixed color, were red, yellow and blue. From these primary colors the secondary colors orange, green and purple could be mixed from combinations of two primaries. The result when all three primaries were mixed was black. This is the opposite of the result when all primaries are mixed in light.
Color in pigment is reliant on light. It depends on the reflection of the specific color. White light is a mixture of all colors and when a color is present only that color is being reflected. For example, in red pigment, all other colors except red are absorbed. Red is reflected and this is what the eye perceives.
Artists use these attributes of pigments in painting. Great examples can be found in any art museum.