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Subject: Lime painting on plaster

Lime painting on plaster

From: Tobit Curteis <tc>
Date: Friday, November 2, 2001
I would agree fully with the sentiment that one should have a clear
understanding of the environmental factors involved with the
deterioration of the painting (in addition to any other contributory
factors). However, if the loss of cohesion of the pigment layer is
due to salt movement as a result of water vapour activity, then a
consolidation technique such as limewatering which involves the use
very high levels of liquid water appears rather curious. Even a
saturated solution of limewater contains only a tiny percentage of
calcium hydroxide, and despite extensive testing over many years,
the efficacy of the treatment remains in doubt. Even assuming the
treatment works in theory, if the painting is sensitive to moisture,
then the introduction of the levels of water needed to carry an
effective level of calcium hydroxide could be disastrous.

With regard to nebulisers and other spray techniques, this
presumably envisages the use of an organic consolidant (rather than
an inorganic option such as limewater).

Why are such widely differing treatments being suggested when there
is no knowledge of the painting ?

We come back to the same point I made in my original response. What
is the painting made of? Why is it deteriorating ? Have the causes
of deterioration been brought under control ? Only once these
questions have been properly addressed should we be looking at
possible treatment methods (let alone whether an organic or
inorganic consolidant is appropriate).

Tobit Curteis Associates
36 Abbey Road
Cambridge CB5 8HQ
+44 1223 501958
Fax: +44 1223 304190

                  Conservation DistList Instance 15:36
                 Distributed: Tuesday, November 6, 2001
                       Message Id: cdl-15-36-006
Received on Friday, 2 November, 2001

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