(Roger - you're subscribed as ROMER@EE.ROCHESTER.EDU. Has this changed
permanently?)
Wayde,
We just completed our second daguerreian workshop this last weekend
and the students were taught how to house daguerreotype plates. Never
put the glass in direct contact with the image surface. Anything
pressed against the imaging particles can disturb them. Also glass is
less stable than we think and can deteriorate and decompose over time
leaving a residue on the image.
The correct method is to cut a spacer to hold the glass away from the
plate. This spacer can be made from two or four ply 100% rag mat board.
The ones we use here are four ply and cut to give approximately a 3/8"
border around the image. In other words, a spacer should look like a
small window mat. The glass, mat and plate are then sealed with
Filmoplast P-90 tape (available from Light Impressions, Gaylord
Brothers, University Products, and other archival supply companies).
I hope this helps. Verbal descriptions of a visual procedure can be
very difficult. If you want to discuss this further, please contact me.
Roger Watson
Conservation Lab.
George Eastman House
Rochester, NY
(716) 271-3361 ext. 323
rwatson@geh.org