Casein paint is made from milk casein(milk protein). It’s dries quickly leaving a moderately water-resistant, matte surface. The Art Store has Richeson/Shiva Casein Paint. We’ve sold casein to be used in restoration of color and design on ancient pottery pieces. With canvas being too flexible of a surface, casein paint is best used on rigid or firm surfaces. The Art Store carries a number of boards appropriate for this medium, we’d be happy to help you choose the right surface for you.