Collections
Temperature and Humidity
Generally, a book and other archival objects need a stable temperature of between 16ºC and 18ºC and a location where the RH remains between 40% and 50%. This will ensure that the conditions are not too humid and not too dry.
High humidity
If the environment is too humid and too warm, mould growth can appear. This will lead to the staining and weakening of objects.
- Effect of mould growth on paper
Dry environment
If the environment is too dry (30% RH or lower), paper and leather can become brittle. This can occur during winter when the heating is on and windows are closed.
Fluctuating environmental conditions
Objects deteriorate at a faster rate if the temperature and relative humidity of the storage area fluctuates from one extreme to the other on a regular basis. When this happens, paper and leather will swell and shrink alternately, as they absorb and loose water causing them to crack and distort. This can occur above radiators that heat and cool rapidly. It also occurs in attics that can be very hot during the day and very cold during the night.
By removing items from an attic or from a damp cellar to a more favourable environment, it is possible to extend their life span as much as tenfold.
