Roberson Rabbit Skin Glue is a ready-made size used to prepare canvas for painting. Size is used to plug pores in the surface of a canvas which would otherwise allow paint to seep into the material. This provides a stable and even surface which displays colour more effectively. This is a transparent size, which will allow the natural tone of your support to show through. The glue must be warmed in a pan of hot water before use; it can then be applied directly to the surface of the canvas. Once the glue has dried, the canvas can be painted on or primed.