I'm learning how to made ambrotypes using black plexiglass. I made the one attached in a workshop held recently in Oaxaca. The conditions of the darkroom and equipment were less than precarious, and I haven't develop the skills needed, so don't judge the piece. My concern is what could be the archival life of a piece made in plexiglass using the traditional wet collodion technique, fixed with a cyanide based fixer. Would it really last? there is a way to know if an ambrotype or tintype is correctly fixed?. I would love to know that I can offer a lasting image to the probable customers.