Similar to applying a basecoat primer when painting a wall at home, canvas must also be primed using a ground. Because canvas is a porous surface, paint can seep into its fibers like a sponge. Priming the canvas prevents this seepage. The most common ground used is gesso, which should be applied in several coats. Gesso can safely be used with both oil and acrylic paints. Canvas is available already primed with ground, or in the raw. Canvas board and pre-stretched canvas are generally pre-primed. You may even want to gesso pre-primed canvas to ensure maximum archival standards and premium surface quality.