Figure 1. Structures of natural and synthetic pigments.

(A) flavone, a yellow pigment produced by paints; (B) carminic acid, a red pigment produced by scale insects; (C) copper phthalocyanine-blue, a blue pigment of the synthetic phthalocyanine family; (D) benzidine yellow, an azo pigment of the synthetic arylide family; (E) PV19, a red pigment of the synthetic quinacridone family. Each molecule is colored to match its perceived color.