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Leather
Storing and displaying leather
Ideal conditions for storing leather
Ideally, objects made from leather, hide and skin should be displayed and stored in a clean, well ventilated environment where temperature is constant and moderate-in the range 18–220C.
If this cannot be maintained, the maximum temperature should be 250C.
Relative humidity should be kept in the range of 45–55%. In very dry conditions with the relative humidity below 30%, leather dries out and becomes brittle. High humidity, that is, above 65%, encourages mould growth.
Parchment and vellum are very sensitive to changes in relative humidity, and experience considerable dimensional change as they absorb and release moisture.
Leather must be protected from environmental fluctuations and dust and insect attack. Display cases and layers of storage provide this type of protection.
Lighting levels should be kept to a minimum, particularly for dyed leather. The brightness of light on undyed leather should be 150 lux or less; and on dyed leather it should be 50 lux or less.
A UV content below 30 µW/lm and no higher than 75 µW/lm is preferred for undyed and dyed leather.
Avoid exposing any leather to bright spotlights or direct sunlight, because these can cause leather to fade, discoloured and dry out.
General storage guidelines
Good housekeeping is essential in the care of leather. Vacuum and dust regularly. This helps to minimise mould, insect and rodent attack.
Protect leather objects from dust using Tyvek dust covers, unbuffered acid-free boxes or acid-free tissue.
Check objects regularly to detect mould and insect infestations early.
Leather objects should be fully supported in storage and on display. They should be supported in their desired shape, so that if they harden later there will be no need for reshaping.
Store long leather pieces horizontally to make sure they are supported fully and evenly.
If three-dimensional objects are unable to support their own weight, then they should be supported internally. The form of the support depends on the shape of the object and the weight of leather to be supported. You can support and fill rounded items with unbuffered, acid-free tissue paper, or chemically stable polyethylene or polypropylene foams. You can make supports for other shapes using these foams.
Leather clothing and large objects such as saddles should be fitted on a dummy or a mount made-to-measure. Stable materials, such as the above-mentioned foams, linen, Dacron and most metals can be used in the manufacture of these supports.
Avoid sharp folds or creases in the leather. This helps reduce cracking.
Because leather products are naturally acidic, they should not come into contact with buffered, acid-free materials: these materials are alkaline and potentially damaging to leather.
Storage cupboards and furniture should be made of painted metal-these provide a stable and neutral storage environment for leather objects.
If you have wooden storage and display furniture, it should be sealed and lined with impermeable coatings, for example, clear polyurethane or laminates. This reduces the risk of reactive chemicals from the wood affecting the leather objects or the metal components associated with the objects. Remember, sealants and glues should be fully dry and cured before putting objects into the storage environment.
Standard conservation-quality mounting and framing are usually adequate for the protection of art or documents on parchment.
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