Ivory Brooch with watercolour portrait

Nicole Rowney <icssyd [at] ibm__net> writes

>A brooch made of ivory with a watercolour portrait has come to us
>for treatment.
>...
>Ideally we would like to remove the varnish then consolidate the
>watercolour, however the watercolour is extremely fragile and
>soluble.

You provided no information on the varnish, so it is difficult to
determine what steps should be taken regarding the cupped area of
pigment.  I would advise you do solubility tests on the varnish to
determine its nature.  Then a conservation course would be to place
the ivory into a chamber with the solvent system the varnish is
soluble in, then observe any change.  One should find that the
varnish will soften which in some cases will result in reattachment
of the cupped area(s).  A consideration, however, is that the
varnish might also have a tendency to be absorbed into the ivory
which could carry any staining along with it.  To avoid this
possibility you must also examine and test the preparation of the
ivory for painting which the artists most assuredly must have done.
A ground layer or at times complex additions were made to ivories
that were painted with portraits.

A wonderful article on such objects was published in the AIC
Preprints in 1981 by Clifford Chieffo, "Problems in conserving
portrait miniatures on ivory".  The source of the staining might
also come from such composite structures.  In other words, a
considerable amount of research, testing and examination are
necessary prior to any treatment.  I hope this is helpful.

Niccolo Caldararo
Director and Chief Conservator
Conservation Art Service

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                  Conservation DistList Instance 12:34
                 Distributed: Saturday, October 3, 1998
                       Message Id: cdl-12-34-005
                                  ***