We paint on hardboard, as many knife painters do, not on canvas. Thick applications of paint could break if the canvas were rolled. Many of the great masters painted on natural wood or hardboard panels, including Picasso. The problem with natural wood is its tendency to crack or “check” over time. Hardboard is essentially homogenized wood, so it doesn’t crack. (Many of us are more familiar with the name “Masonite” than “hardboard,” but we cannot use the name “Masonite” anymore since it is copyrighted. Calling it “hardboard” avoids this copyright problem.) Hardboard is made by exploding wood fibers with steam and then pressing them back together into sheets without any additives or glues. The lignins and other natural substances of the wood hold it all together just as they do in the original wood. To prevent warping, we back the panels with a frame, as shown in the picture.