Lighting For Leather
Leather, like many other materials, is sensitive to light. To accommodate both the continued preservation of dyed leather and the patron's ability to see the objects, the maximum amount of light that should be allowed when displaying leather is 50 lux. Overexposure can cause discoloration. Undyed leather can handle up to 200 lux without fear of damage.
Moisture Levels
Without the proper level of moisture, leather will become fragile, brittle, and more easily susceptible to damage. Leather is a moisture absorbant material; it takes in moisture from the air and will swell if the relative humidity (RH) rises and will shrink when the RH falls. This fluctuation can cause breaking, separation of connected pieces, and other types of damage.
Storage
Store leather goods in acid-free paper or boxes in climate controlled facilities keeping in mind appropriate RH and light levels.
Used with permission from Holmer Lewis © 2014
Best Relative Humidity Levels for Leather
45% - 60% RH
Dyes tend to fade more quickly at high RH than low RH. High RH also increases bio-degeneration, although control of RH will not necessarily prevent biodegeneration.
The relative humidity that is best for leather is not the best for all materials. Leather is often combined with other materials that might not do as well in the humidity range recommended for leather. The model carriage (left) is an example of a mixed medium object. The back cover is leather, but the majority of the object is wood.
Most objects in a museum will do well in the 45%- 60% RH level.
RH should never go above 70% -- once that threshold is crossed there is an increased danger of mold growth.
Handling
When handling leather, is recommended that one use clean, dry hands. Due to the porous nature of leather, it can pick up any dirt, grime, or oils that might be on one's hands. If the leather is brittle, use care when handling it.
Labeling
Best practices of labeling dictate the use of hang tags when labeling leather goods. Leather is porous and will absorbed any ink marking that might be used on it, making those marks permanent. Permanent labeling is strongly discouraged. Tags should be tied to the object and be easy to remove without damaging the object.
If one cannot tie a tag on the object, there are some alternatives:
1) Use the tissue wrapping the object as the identification label and write the number on the paper.
2) Tuck the tag into the object e.g., in the pocket of a leather wallet.
3) Photograph the item and identification number and place the photo on the storage box. The last method works well because even if the object and the identifying label get seperated, the image on the box will help staff reconnect the two.
