Most works in two dimension involve a process whereby color is applied to a surface. In prints this color is often black, but it is still a coloring agent. The surface often depends on the technique being used. For instance oil paintings are best supported on a canvas surface, watercolor paintings are best supported on paper, tempera is best supported on wood panels, etc. In the case of a fresco the surface and the binder are one and the same - the plaster. The pigment is mixed into that plaster and then it is applied. Pigment is the color that is mixed with a binder, which is then applied to a surface. In an oil painting the pigment is mixed with oil. The pigment is usually a powder.