paint, mixture of a pigment and a binding medium, usually thinned with a solvent to form a liquid vehicle. The term includes lacquer, portland cement paint, printing ink, calcimine, and whitewash. Paint is used to decorate or protect surfaces and is generally applied in thin coats which dry (by evaporation or by oxidation of the vehicle) to an adhesive film. Industrial finishes are usually applied by spraying or immersion and are often hardened by baking. Pigments, finely ground, impart color (including black and white) and affect the consistency, crack resistance, and flow characteristics of paint. They may be manipulated to produce glossy, satin, or flat finishes. Oil paints are pigments dispersed in a drying oil such as linseed oil, castor oil, or tung oil. These oils are diluted with a thinner, usually turpentine; metallic salts that catalyze oxidation of the oil may be added to increase the rate of drying. For water paints, pigment is dissolved in a mixture of water with a binder such as glue or casein, or emulsified in a latex polymer. Latex emulsion paint provides such excellent durability and color retention that it now dominates the paint market. Enamel paints contain varnish and usually dry to a hard, glossy finish. Industrial lacquers (widely used on automobiles and furniture) are valued for rapid drying to a hard finish. The vehicle is commonly pyroxylin in an organic solvent. Baked acrylic finishes have recently become popular for industrial products such as automobiles and appliances.
See C. R. Martens, Technology of Paints, Varnishes, and Lacquers (1968).