The University of Arizona
 

Glossary of Paint Terms

Acrylic: A water-based paint composed of synthetic polymer resin and pigments. The resin is suspended in water and may be diluted but once dry, they are no longer water-soluble.
Casein: A protein based paint that is opaque and matte. Traditionally made from the washed curd of soured skim milk mixed with limewater, pigments, and fillers. They become insoluble with time.
Gouache: A water-based paint that is opaque and matte. Usually made from gum Arabic, a chalk-like filler, and pigment. The term can refer to both the medium as well as to the technique of using watercolors.
Encaustic: A painting technique which combines color pigment with hot wax and resin. This mixture of materials is applied in its semi-liquid form to a panel or other support as paint and then fused to the surface with heat.
Oil: A luminous paint that implies the use of a drying oil, such as linseed oil, with pigments. Drying oils form solid films upon exposure to the air.
Tempera: A water-based paint that becomes opaque with a soft sheen, and becomes sufficiently insoluble so that over painting is possible. Egg tempera is made from egg yolk; glue tempera is made from gum Arabic. Poster paints or show-card colors are a type of water-based "tempera" paint sold in jars with a gum or glue binder. After drying, tempera paints resemble the color of their original dry state.
Watercolor: A water-based paint that is a translucent wash of pigment. Usually made from pigments, gum Arabic, and water on a light colored ground or support. Highlights may be attained by thinning the paint with water so the ground shows through.