Cheers, cspear. I am using D3D and linear workflow (or trying to). I had IC set at 90 or 95 for the raytrace bit but never went above 50 for the IDL range as on a previous thread I was told not to as it led to light leakage and artifacts (the same problem I'm trying to fix). I'll have a crack with both maxed and see what happens. It might take a while!