Copper in starch paste

We are undertaking book conservation work, consisting mainly of the
removal of old restorations. These restorations were made in India
(probably in the 1950's) with translucent paper and starch paste
(analysed by spot tests). The odd characteristic about this adhesive
is its greenish hue. In order to understand why it had this colour,
we have analysed it by X-ray spectrometry, which revealed the
presence of a considerable amount of copper in its composition.

In the literature we have not found any information about the
combination of starch paste with copper. We thought maybe it was
some insecticide or fungicide compound added to this bio-susceptible
glue, but there is nothing on this subject in the articles we have
found. Does anyone know anything about this starch paste/copper
combination?

Silvia Sequeira and
Laura Moura
Paper and Book Conservators
The Tropical Research Institute (IICT) - Portugal


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                  Conservation DistList Instance 21:35
                Distributed: Tuesday, December 18, 2007
                       Message Id: cdl-21-35-019
                                  ***