scratching technique on canvas

[beanpoleuk]

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

 

[Mr.Micron]

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.

 

[ad fez]

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