Rabbit skin glue forms an important part of gesso, which is still used as a primer or preparation of a wooden board or canvas, though these days has mostly been replaced by white acrylic paint.
In traditional oil painting as practiced by the Renaissance painter, skin glue was being mixed with chalk or marble dust and applied as coating on canvases. Then this was sanded down to an even level, and the process would be repeated a couple of times.
This was necessary because the linseed oil that forms the base of most oil paint contains linolenic acid which would otherwise destroy the canvas fibres over time.
