A word of warning. All glass is not the same. I went into the local Aaron Bros. frame and art supply store and inquired about glass. They had several nice varieties, including some very heavy glass that I thought would hold negative in contact (It's all about contact) with the paper. I happened to ask at the last minute if there was any anti-UV in the glass. They said, "Yes, all our glass has UV blocking" This is not good for alternative printing. UV makes it work. Choose your printing glass with care.