Dyes and Pigments

Color scientists use the term "colorant" for the entire spectrum of coloring materials, including dyes and pigments. While both dyes and pigments are sources of color, they are different from one another. Pigments are particles of color that are insoluble in water, oils, and resins. They need a binder or to be suspended in a dispersing agent to impart or spread their color. Dyes are usually water soluble and depend on physical and/or chemical reactions to impart their color. Generally, soluble colorants are used for coloring textiles, paper, and other substances while pigments are used for coloring paints, inks, cosmetics and plastics. Dyes are also called dyestuffs. The source of all colorants is either organic or inorganic.

Colorants are classified according to their chemical structure or composition (organic or inorganic), method of application, hue, origin (natural or synthetic), dyeing properties, utilization, and, sometimes, the name of the manufacturer and place of origin. The Society of Dyers and Colourists and the American Association of Textile Chemists and Colorists have devised a classification system, called the Color Index, that consists of the common name for the color, and a five-digit identification number.