Limestone impregnated with cellulose acetate

While working on a painted Egyptian sculpture limestone I've found
that it is completely impregnated with cellulose acetate (CA). I
have no idea when this treatment was done. C.V. Horie (Materials for
Conservation) reported that CA in acetone became widely available
during World War I and was used for fixing pigments on stone in
1923. Another record is F. Rathgen: Die Konservierung von
Altertumsfunden, Berlin, 1926, who suggested CA in acetone for the
consolidation of painted limestone.

Since the sculpture was excavated in 1927, the treatment possibly
was carried out immediately after.

Today, the treatment is not visible, the polymer seems to have
disappeared from the surface but still rested deeper in the stone.
The CA is still soluble in acetone and shows no discoloration. The
paint layer on the sculpture shows powering and flaking and needs
consolidation.

Who has experiences in painted stone sculpture treated with CA?
Where there any damages of the paint layer by CA films? As the CA
can not be reduced before the new treatment is carried out, the new
consolidant has to be compatible with CA. Who has experience in this
case?

Olaf Pung, student of conservation.
Fachhochschule Hildesheim, Germany

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                  Conservation DistList Instance 12:36
                 Distributed: Tuesday, October 13, 1998
                       Message Id: cdl-12-36-011
                                  ***