Laminating canvas is not a terribly good idea. The lamination only sticks to the high points of the surface texture and the result looks bad because there are many small "bubbles" where the lamination is not bonded to the canvas. If you're going to laminate, use a matte-finish paper. It's smooth enough for the lamination to bond to the entire surface, but less prone to air bubbles being trapped between the media and lamination than glossy stock. If you gotta use canvas, protect it with a spray coating, not lamination.