This illustration is for the primate diaries this week. The chimp is drawn with ink and wash but the background is created with a type of paint called Casein paint. Derived from milk casein, is a fast-drying, water-soluble medium. 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 but here I am using it in 4 ply Bristol board. Casein paint is reworkable and can be used for underpainting. It generally dries to a matte finish. This was the paint of choice for illustrators prior to the 1960s but once Acrylic came to be most illustrators dropped Casein paint but I think I will be exploring it more in the near future.