scratching technique on canvas


Air-Valve Autobot!
My daughter has several canvas boards just sitting in a cupboard and as I was thinking of trying out the scratching technique on a tiger picture, would these canvas boards be okay for scratching hairs, highlights etc ? Do I need to prep the canvas first
most prep the canvas with Gesso, but scratching works great on canvas. also erasing as well , Sometime when you want a softer highlight you will use an eraser rather than scratching.
it depends on what effect you want, but its worth adding most use the round bladed razor rather than the pointy type, don't want to pop the canvas, you also get a different scratch if you pull it towards you rather than pushing away from you