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How to keep for a while what you want to keep for ever |
Tim Padfield April 24, 2005
This article is the lecture notes for the museology course at Denmark's Library School, April 2005. Much of the content is more thoroughly treated in other articles on this website.
Preventive conservation seems to be a clearly understandable phrase, but it has two interpretations. One method of preventive conservation, very widely used in the past, was to varnish everything that came into the care of a museum, or dip it in molten wax. Nowadays we are not so proud of this legacy of greasy dark brown surfaces, concealing paintings, bronze, iron even wood, with a uniform patina. But we use a modern equivalent: a transparent acrylic resin, Acryloid B72, whose use on a Faberge diamond encrusted cigar case caused me to pronounce it a fake. Fortunately a colleague insisted on shining a uv lamp on the soft, easily scratched and optically dull stones. The characteristic blue green phosphorescence of diamond saved the priceless relic from the charity shop window.
Far more invasive techniques come under the heading of `preventive' conservation. For example, heating archaeological iron to 800 degrees to volatilise the chloride which may or may not be present and may or may not lead to corrosion. The heating destroys the crystal structure which would reveal the way the object had been manufactured.
The alternative definition of preventive conservation is controlling the environment so it is not necessary to smear varnish over things.
I will look at the environmental agents of decay and describe how their damaging effect can be minimised, first in principle, then in practice.
The entire article is in pdf format.
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