Casein paint
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Casein paint, derived from milk, is a fast-drying, water-soluble medium used by artists. It generally has a glue-like consistency, but can be thinned with water to the degree that fits a particular artist's style and desired result. It can be used on canvas panels, illustration boards, paper, wood and masonite. Because the dried paint film is inflexible and brittle, it should not be applied in heavy impastos on flexible supports such as canvas or paper. Casein paint is reworkable and can be used for underpainting. It generally dries to a matte finish.
Casein paint has been used since ancient Egyptian times as a form of tempera paint, and is still used today. Some of the qualities that artists value casein paint for is that unlike gouache, it dries to an even consistency making it ideal for murals. Also, visually it can resemble oil painting more than most other water based paints, and works well as an underpainting.
Native American artist Oscar Howe, of South Dakota used casein extensively.