Dyes and pigments are substances that are used to impart color to liquid solutions and solid materials. Dyes are generally soluble (or partly soluble) organic compounds used in the textile industry to color fabrics, textile fibers and clothing. In additional to their application in textiles, dyes are used on paper and leather. Dyes are also added, under government regulation, to foods, drugs and cosmetics. Pigments, on the other hand, are insoluble inorganic and organic chemicals that are added to color paints, glazes and printing inks.

Natural plant materials have been used to dye wool since ancient times. Tyrian purple, from the shellfish murex, was a dye reserved for the emperor; this dye was worth several times its weight in gold. Woad, used since the time of the ancient Celts, produces a blue dye. Dyer's broom, or greenweed, yields a yellow dye, often added to...