Painter's canvas is a term used to describe the surface on which a painter applies their paint. It can be made of a variety of materials, such as linen, cotton, or even plastic. The most common material used for a painter's canvas is tarp, which is a heavy-duty, waterproof material that is often used in construction and other outdoor activities. Tarp is an ideal material for a painter's canvas because it is durable and provides a smooth surface for painting.