Natural, inorganic pigments come from metallic oxides and salts. Their sources include cobalt, copper, iron oxide, magnesium, manganese, and mercury as well as sulfur, titanium dioxide, and zinc oxide. They have been used as color sources since man first began to paint. Colors include cobalt, umber, and ultramarine. Organic pigment sources are plants or animals. Colors may be ivory, indigo, and sepia. Rose madder genuine is an example of a natural, organic pigment.
Today, many pigments are synthetically made from dyes. Alizarin crimson, azo yellow, and quinacridone colors are in this group. They are frequently pure, bright transparent colors.