Moving Targets for Preservation

According to recent reports by the Image Permanence Institute, the 70 degree/ 50 % relative humidity target for collections storage environments is not only outdated and unsustainable, it was never optimal in the first place. What started as a best guess, based primarily on human comfort, became accepted practice in museums and libraries for decades. However, “research at preservation science laboratories in the United States, Canada, and abroad provided data to show that wider fluctuations in relative humidity and temperature were not necessarily damaging to collections.” The old standard is “difficult to achieve, even harder to maintain, expensive and not always necessary.”

But where should collections stewards aim? The target is now always moving based on seasonal drift and material types. For instance, moderate temperatures are not appropriate for preserving certain materials. Most photographs and films should be chilled. For optimal preservation, different types of materials should be stored together and in smaller, customized environments where possible. These separate measure do not have to be costly. A frost-free refrigerator/ freezer can house a photograph collection safely. Many can be stored in the freezer section, while special types, such as glass plate negatives, can be stored in the refrigerator section. Polyethylene or polypropylene boxes with silica gel inside can provide affordable storage for humidity-sensitive materials such as leather and metals.

IPI’s “Quick Reference” guide can help to plot environmental priorities for various collection material types. Further, The University of Illinois Library is developing another tool to help collection managers make item-level and collection-level preservation assessments and identify actions to improve conditions. The Preservation Self-Assessment Program is a free online method to target solutions. The program is new and currently limited to library materials–books, papers, photographs, and film–but is worth exploring for museum collections too. The Connecting to Collections online community will introduce this tool more fully in an upcoming free webinar, scheduled November 5, 2014.

As collections stewards, we shouldn’t be afraid that the monolithic standard has been debunked. Preservation knowledge has grown more complex, but we are all crafty and resourceful enough to adapt to the new moving targets.