Casein is a protein derived from the dried curds of skim milk, a natural emulsion containing a small amount of butterfat suspended in water. The skim milk is allowed to sour, or made to sour by adding a weak acid or an enzyme (rennet). The resulting curds are separated from the whey, dried, and ground up into a white powder.
Casein paint has a rich and ancient history. Prehistoric artists found that there was an abundance of pigment to be found in the earth, as well as from plants and berries. But pigments were not enough by themself, a binder was needed both to carry the pigment and to fix it to a painting surface. They found that milk curd, eggs and the sap from certain trees, along with other things, could be processed into suitable binders.
The paint these early artists made from milk curd is the forerunner of today’s caseins. Caseins were widely used by many artists until replaced by the use of acrylic paints. They have an exceptional integrity of color and always dry to a perfect matte finish. In more recent years ready-made casein colors in tubes have become increasingly popular.
