"The environment (temperature, relative humidity, air quality
and light levels) in the exhibition galleries and storage areas
has a very important effect on the long term preservation of objects
in museum collections. Many organic (and also some inorganic)
materials are quite sensitive to light - both in the ultraviolet
and visible ranges - and will suffer degradation from photochemical
reactions. For example, the colors of many textile dyestuffs,
as well as paint pigments, will fade and change as a result of
such effects. Air pollutants will also cause chemical changes
in sensitive materials.We can prevent and minimize many of these
effects by keeping the storage areas dark, exhibit light levels
carefully controlled, and the air in all collection areas clean....
"What we need to know, in order to design and maintain efficient
and cost effective climate control systems, is what the allowable
limits are within we must maintain the museum environment to prevent
damage to occur. SCMRE researchers have focused on these questions,
and developed a far better quantitative understanding of the issues
than existed previously. Using an extensive database of mechanical
properties of materials (strength, elasticity, etc.), measured
under various conditions and as affected by aging processes, in
combination with sophisticated computer-based models, they are
able to define environmental "envelopes" that represent
the optimal conditions in which to safely preserve the collections
in museums nationwide.""
Center for Materials Research and Education
Ch. 4: Museum Collections Environment (download PDF format file),
I, Museum Collections, Museum
Handbook, Museum Management
Program, National Park Service.
Kerschner, Richard L. and Jennifer Baker. Practical
Climate Control: A Selected, Annotated Bibliography, JIAC
the dewpoint and frostpoint temperature at a given ambient temperature
and given ambient relative humidity.