I had thought that might be an issue, the polyurethane, but suspected if it was, the emulsion likely wouldn't survive the developer. Of course, I could be entirely wrong. I will contact Rockland Colloid and see if they don't have a solution to the problem. I had purchased some Knox gelatin that I would step up to from the polyurethane once I got comfortable with applying the LL, I think a bit of a test is in order. Two plates, one coated with gelatin and the other with polyurethane, and I'll know if its the sub or not. Thanks.