This looks like it was a fantastic workshop! I took the Campbell Center's Care of Photos I and II courses this summer with Gary Albright. We learned mostly preservation measures since it was an introduction but I have a photo that is stuck to glass. It is only stuck in about a 1/2 in. By 3 mm area. The photo is from the late 20th cent. I think it is probably gelatin dop. I don't suppose you'd be willing to share any of the unsticking photos from glass techniques by email? Gary told me to leave it be but it bothers me because the glass is dirty and old and probably wouldn't allow for a good scan. I understand if you can't share.