Glass plate negatives

Noel Carmack's posting regarding glass plate negatives mentions that
she is dealing with some "dry-plate (collodion) glass negatives."
This is confusing since dry plates have gelatin coated on glass
while the earlier wet plates have collodion coated on the glass.
This makes a difference since consolidants or cleaning agents
suitable for one type of emulsion may be inappropriate for the
other.  Before implementing any type of treatment, the coating
medium on the glass needs to be identified.  A good starting place
for this would be Constance McCabe's article "Preservation of 19th
Century Negatives in the National Archives" Journal of the American
Institute of Conservation, spring 1991, V.30, number 1.

Paul Messier
Conservator of Photographs & Works on Paper
Boston Art Conservation
77 Griggs Rd. Brookline, MA 02146
617-738-7072
Fax:  617-738-8841

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                  Conservation DistList Instance 9:31
                Distributed: Wednesday, October 4, 1995
                        Message Id: cdl-9-31-003
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