Sennelier Acrylic Gesso is a mixture of acrylic resins and various Whites (or colors) that creates an indelible film and enables paint to adhere to canvases and other surfaces. - Sennelier Acrylic Gesso - 500 ml, White, Semi-Absorbent Gesso for WatercolorSennelier Acrylic Gesso, SEMI ABSRBNT/WC 500M - Sennelier Semi-Absorbent Gesso creates a matte, porous surface similar to watercolor paper that allows for improved penetration and diffusion of color for watercolors, egg tempera, gouache, or casein. It also provides a resistance to water that is greater than traditional watercolor paper.