There just aren't many choice left for true AN glass. Focal Point will custom cut your glass and edge it with
either 2mm or 3mm stock, and they're reasonable. Etched picture frame glass isn't the same thing - it breaks
way easier and sometimes causes minor optical issues the way it diffuses the light. At one time I had samples of
AN glass from all over the world. The best came from Belgium. It's a fussier topic in an enlarging carrier than a
contact frame.