DecoArt Premium Acrylic White Gesso is designed to act as a primer that prepares a surface for painting. It provides a good tooth for paint adhesion, stiffens the surfaces of canvas and board, prevents paint from soaking into the base material and ensures a more even and long-lasting painting surface for both acrylic and oil paints. Although many canvases are pre-primered, it's still worth applying a coat or two of gesso for a really even surface to work on before beginning to paint.