When drawing on very smooth calfskin or goatskin, I am able to use two methods, sponge-stamping and decalcomania, that are more commonly used in painting than in drawing. This is because ink does not quickly saturate the skin and dry, as it would on paper. Rather, it sits on the surface and can be manipulated for a few seconds. Also, it is easy to remove cleanly with a knife, so it does not matter so much that these methods are rather messy.
I got the idea of using a natural sponge as a drawing tool from watching footage of Eyvind Earle painting a tree trunk. The natural patterns in the sponge approximate other natural patterns (such as the outlines of distant foliage or lichens growing on wood) very well.
Decalcomania is a technique that involves spreading wet paint or ink on a surface, then pressing glass or paper or something else flat into it while it is still wet. When the pressure is removed, the paint or ink gathers into fascinating patterns. The painter Oscar Dominguez helped to make this method popular, and no artist used it more extensively than his fellow Surrealist Max Ernst (who was, in my student years, a major influence on me).
These are two oil paintings on canvas that I made when I was nineteen years old. I painted solid areas of light color, and then spread dark, thinned-out oil paint over them. I pressed plastic wrap against them for the decalcomania patterns. After I turned away from Surrealism and to medieval influences, I abandoned this method for years. Only recently have I begun to experiment with it again, as in the sky of my drawing of St. Hugh of Lincoln. No matter how repugnant I now find the ideas animating Surrealist art, I cannot deny that the decalcomania method can create very beautiful images. To refuse to use it in my religious art would be something of a cheat on God.