Mural

Amir Hosein Karimy <ahkarimy [at] yahoo__com> writes

>I have a problem with a mural decoration from Safavid period (400
>years old).  It is a painting on plaster with water soluble medium.
>About 200 years after creating these decorations, they covered them
>with a layer of gypsum plaster. How can i remove this plaster? With
>mechanical method all the pigments will be removed. do you have any
>idea about this?

About 12 years ago, I believe Chandra Reedy et al were experimenting
with using Sulphate-digesting bacteria as a means of softening
sulphate crusts on stone, at least that is my memory of it.  I was
interested in its application as a way to remove hardened plaster
from porous ceramic surfaces (results of sloppy restoration).  I
just did a search on CHIN but could not retrieve anything and I
never heard about the outcome.  Does this ring a bell with anyone?
Of course bacteria have to be applied with an aqueous medium so that
may be useless, but with some control perhaps...

Alternatively, in a similar circumstance, as a last resort I was
able to reduce a hard insoluble crust to an extremely thin layer
with a small glass bristle brush. Coating with a synthetic resin
then made the remaining crust translucent enough to allow the paint
beneath to be seen.  This method would only be suitable under
certain conditions and could even be damaging if not performed with
utmost care and magnification of the area being treated.
I hope something above might be helpful,

Linda S. Roundhill
Art and Antiquities Conservation
18121 157th Ave NE
Woodinville, WA 98072
425-481-0720


                                  ***
                  Conservation DistList Instance 17:8
                   Distributed: Tuesday, July 1, 2003
                        Message Id: cdl-17-8-002
                                  ***