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 sure this is going to be of any help, my experience is
limited to embossed and stamped out Chromolithographs commonly
called scraps or chromos. I have handled hundreds of these in my
collecting and dealing days (pre-conservation career). Although A.
Allen and J. Hoverstadt in History of printed scraps, 1983, New
Cavendish Books, London, mention that "the sheets were coated with a
gelatine and gum film before they went through the embossing
machine" (p.9), most of them were  water resistant as I commonly
had to soak pages of albums in warm water to free the scraps from
the pages where they had been glued with starch paste (and sometimes
left them in a bath overnight). I had only one accident with the
process (I am still lamenting it) it was a large giraffe on very
thick paper very heavily embossed, as soon as she hit the water, the
printing lifted and curled up into a gelatinous mass. There was a
few more of that type (heavy paper) in that album dated around 1890
which I removed with scalpel from the page.  I am sorry, I do not
know the origins of the giraffe and its companions.

D. Rogers


                                  ***
                  Conservation DistList Instance 16:72
                   Distributed: Monday, May 19, 2003
                       Message Id: cdl-16-72-006
                                  ***