The care of skin clothing in the British Museum
Skins are made into durable leather by the process of tanning.
There are three main processes: vegetable tanning using the tannin
that occurs naturally in certain plants, mineral tanning using
metallic salts, and oil tanning with oils and other fatty
materials.
Many of the skins that are acquired by the Department of Africa,
Oceania and the Americas (formerly Department of Ethnography) are
untanned or only partly tanned; they are less stable than fully
tanned skins and more likely to decay.
Objects made from skins are easily affected by their
surroundings. Humidity, temperature, light and insects can all
cause damage. The relative humidity needs to be kept constant at a
suitable level: a dry atmosphere can lead to splitting, too humid
conditions can lead to the growth of mould.
Once in a museum such skins may loose much of their flexibility,
as they are no longer being worn or kept pliable by Inuit methods
such as chewing or scraping. In the past, collectors often treated
skins with oily dressings to keep them flexible. However,
conservators discovered that the dressings themselves could cause
problems and, as flexibility is now no longer considered essential,
they are usually avoided. In storage, items are gently padded with
acid-free tissue paper to prevent the formation of creases. Good
support on exhibition is also essential.