Temperature and Humidity Concerns

The house in Florida, garage on the left.

When my parents moved to Florida, the family collection went with them.  Most of the items were kept inside the house where temperature and humidity levels were fairly constant.  These items fared well.  But other items landed in long-term temporary storage in the garage where they were exposed to Florida’s high temperatures and high humidity.  Consequently, they suffered.

“Temperature and relative humidity are major concerns in preservation,” according to Laura Hortz Stanton, Director of Preservation Services at the Conservation Center for Art and Historic Artifacts.  “A garage in cold weather isn’t too bad for storage.  But high temperatures can lead to degradation.

“Humidity is an even greater concern,” Laura says.  “You don’t want the storage environment to be either too damp or too dry.  Ideally, the relative humidity should be no less than 35% and no greater than 65%.”  When it’s too dry, the paper can become brittle and when it’s too humid, it can become excessively floppy, as

Acid-free folders and boxes offering
layers of protection.

well as increasing the risk for mold growth.

The conditions that are most comfortable for people tend to be best for collections.  “Spring and fall weather is where collections are happiest,” Laura notes.  To protect against the extremes, she recommends using layers of protection.  Place items within folders or sleeves then place the folders within boxes (everything acid-free, of course!) and the acid-free boxes can go inside plastic containers.  The layers help to mitigate damage that might be caused by unexpected changes in temperature or humidity.

© 2011 Lee Price