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.

The chances are good that a glue or gelatine layer underlies the
varnish.  When varnish is applied directly to most papers, printed
or not, it will penetrate unevenly in those papers which are printed
with non aqueous media.  In order to keep the varnish coat even, the
glue layer is applied first.


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                  Conservation DistList Instance 16:73
                  Distributed: Thursday, May 22, 2003
                       Message Id: cdl-16-73-003
                                  ***