Mold on terracotta

Emily Clough <emily_clough [at] bristol-city__gov__uk> writes

>I am currently treating a Canosa ware terracotta askos whose
>pigmented kaolinite slip has become stained with mildew. The mildew
>is visually disfiguring.
>
>While we would not normally remove these stains, I was curious to
>know whether anyone was aware of the chemical composition of mildew
>stains, and whether any promising strategies for its removal have
>been attempted.

Recently I was handed for cleaning a small terracotta head,
disfigured by small dark specks, presumably mould, on the horizontal
surfaces: the top of the head, the forehead, across the nose and
cheeks.

An initial attempt to remove these, by means of a steam cleaner
using deionised water, was not effective. However, a repeat of the
process several days later did in fact remove all discolourations.
So perseverance pays! My colleague Isabelle Garachon of the
Rijsmuseum in Amsterdam suggested trying a poultice of blotting
paper or paper pulp, or maybe even clay, but as they in the end
weren't necessary I didn't attempt these solutions.

Lindsey Bogle
De Porcelain Studio
Maasdijk 423
4264 AS VEEN
Netherlands


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                  Conservation DistList Instance 16:39
                Distributed: Tuesday, December 10, 2002
                       Message Id: cdl-16-39-011
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