Canvases are generally tightly stretched on to a frame that creates a spring in the fabric when pressure is applied. The more taut the canvas ia the more enjoyable it is to paint on, as the tension in the surface has an element of vibrancy and creates a more rigid surface to paint on. The tightness of a canvas must be the same across the whole frame so that the grain of the fabric is square to the edges, with no skewing. Readymade or pre stretched canvases most commonly have a universally primed canvas stretched on to a wooden frame with bevelled edges or quandrants.