Varnished chromolithograph

Michaela Keil <mikkeil [at] hotmail__com> writes

>I am currently a MA paper conservation student in Cologne, Germany.
>My final project is a varnished chromolithographic map from around
>1900. The very brittle paper has a water-soluble varnish on the
>surface. Part of the printing ink and the varnish are flaking.
>FTIR-spectroscopy analysis indicated a mastic varnish, which is very
>surprising, since mastic usually does not dissolve in water. I am
>interested in hearing if anybody has an idea how this is possible? I
>would also appreciate any information on treatment experiences with
>varnished paper artefacts.

I am not a paper person, but in dealing with coatings, especially
natural resins, I would consider the possibility of a saponification
reaction having taken place. If this coating was washed with a
soap/detergent product at some point in time and not completely
cleared, the end result could be water solubility. Just a thought.

Wendy Leeds


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                  Conservation DistList Instance 16:72
                   Distributed: Monday, May 19, 2003
                       Message Id: cdl-16-72-005
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