Priming with these products transforms supports not usually used for watercolor, such as canvas, painting boards, and wood, into suitable grounds for watercolor painting. Available in coarse and fine textures. - Schmincke Aqua Primer - Coarse, 250 ml jarSchmincke Aqua Medium, PRIMER COARSE 250ML - This 250 ml jar of Coarse primer creates a rough surface on surfaces such as canvas, wood, and board, and restricts the flow of color, resulting in a textured effect. This primer can be tinted with tube watercolor or acrylics. Apply at least 3 layers on the surface with a palette knife or spatula and allow it to dry completely before applying watercolor paint.