My living room walls have a really good quality wallpaper on them though we're now sick looking at it!! I don't want to have to re-paper so wanted to emulsion. However, the wallpaper is cream but it has red rectangles dotted about. I did a couple of test patches to see if it would cover - one with two coats of ordinary emulsion and one with a base coat of Dulux Once and then a top coat of the colour I was going to use. However, the red is still showing through slightly on both test areas. Is there a product that I could use to cover the red - or am I destined to three coats of emulsion? Also, an obscure thought comes to mind - I'm sure I saw something once about using green over red to cancel it out before using a top coat. Am I dreaming or does that work? Any help much appreciated - I really don't want to have to strip and re-paper the walls.