Glass plate negatives

Henrik Gasmus <protze.gasmus [at] t-online__de> writes

>I am a student of photo conservation and I work on gelatin dry
>plates, made in the years of 1929/1930. On all plates the flaking of
>about 5% of the emulsion occurred. I'd like to ask, if there are any
>experiences made with the re-adhering of flaking gelatin emulsions?

Before trying to re-adhere the emulsion, it might make sense to look
into the reasons for this flaking. If it is most likely due to glass
corrosion, you can probably expect further deterioration in the
future and a complete emulsion transfer to a new glass may be
considered the better alternative. If bad storage conditions in the
past are very likely to be the main reason, the emulsion can be
re-adhered with a thin (1-2%) gelatin solution.

However, emulsions from this time tend to expand up to 20% when
wetted. Preliminary hardening in formaldehyde fumes can reduce this
to about 1%. A more detailed description of one of my glass plate
treatment projects is published in: "K. Pollmeier: Die Restaurierung
von Glasnegativen und-positiven von F. W. Murnau", 8. Int.
IADA-Kongress, Tubingen 1995.

Klaus Pollmeier
Advanced Residency Program in Photograph Conservation
Rochester, NY


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                  Conservation DistList Instance 14:3
                  Distributed: Thursday, July 6, 2000
                        Message Id: cdl-14-3-004
                                  ***