Mold on paintings

I have been working during the past 10 months with a range of highly
infested paintings (mostly acrylic on masonite, but also mixed media
and oil on canvas), and try to inhibit the growth of mold with the
application of thymol (dissolved in pure ethyl alcohol and applied
with a spray gun on the reverse of the canvas/hardboard). I work in
extreme conditions (about 95% RH, and most of the private
collections here in Puerto Rico have no air conditioning system and
no dehumidifier).

I recommend to avoid direct contact to the painting layers, as
thymol might react with some pigments and some contents (lipids) of
the binding medium). After leaving the object for about 24 hours
wrapped in plastic foil (mylar, e.g.) to create a toxic atmosphere,
I treated the residues of the mould such as spores and oxidation
products with acetic acid or citric acid locally (5%, dissolved).

Matte surfaces are easier to treat than varnished ones. In the
latter case, the oxidized areas have to be saturated again with a
coating that does not attract a new infestation.

Literature such as 'Fungal Facts' by Mary-Lou E. Florian (Kremer,
New York) might provide a sound insight into this problem. But
still, many questions in this field remain open.


                                  ***
                  Conservation DistList Instance 17:70
                   Distributed: Sunday, May 23, 2004
                       Message Id: cdl-17-70-003
                                  ***