Cold Enough for the Negatives
Posted December 17, 2008
Topics: Daily Life

Plastic based film negatives were a technological wonder when they were introduced by Eastman Kodak in 1889.  Compared to the glass plate negatives that photographers had used for decades they were light weight, flexible and took far less room to store.  The introduction of the plastic film base made the invention of motion picture film possible.  There was a drawback to these new negatives.  The film base was cellulose nitrate, a form of plastic that is chemically unstable and very flammable.  Disastrous fires in photography studios, movie theaters and other places that film was stored and used occurred.  In 1934 acetate based film was introduced as an alternative.  Dubbed safety film because it was less flammable, it gradually replaced nitrate based film.   Much nitrate film has been lost due to physical deterioration and fires or disposed because it could not be stored safely.   Nitrate film that exists today is largely found in museums and archives.

The Ohio Historical Society has approximately 110 cubic feet of cellulose nitrate sheet film and seven rolls of nitrate motion picture film in our photography collections.  This material includes negatives from the Baker Art Gallery, a Columbus photography studio that operated from the 1870s to the 1950s and a collection that documents the training and deployment of the 37th Infantry Division during World War II.  Through November and December Collections Division staff have worked to improve the nitrate storage conditions in the archives stacks.  Research has shown the safest way to store nitrate film is in cold temperatures with low humidity.  Additionally, it should be completely segregated from other archival, library and museum materials.  Freezing temperatures are in fact necessary to halt chemical deterioration of the film and prolong its life.  Freezing the film also greatly minimizes the chances of it catching on fire. With a generous grant from Nancy Wolf Lane we were able to purchase six frost free commercial freezers in which to store the film.

The films were moved from metal filing cabinets to the Society’s conservation laboratory.  Before the collections were placed in the freezers, the negative boxes were double wrapped in polyethelene zip lock bags.  Included in the packages were silica gel packets to absorb moisture and humidity indicator cards to monitor any changes in relative humidity within the packages.  After the freezers were installed, the negatives were moved in and a map of their freezer locations created.  Staff will regularly monitor the temperature and humidity levels in the freezers.  The freezer bank creates the dry, cool conditions necessary to preserve the nitrate negatives, separates the nitrate film from other materials and greatly improves the safety conditions in the archive’s stacks.   With the nitrate negatives safely stored, Collections Division staff can now focus on developing a plan to make the images accessible to the public in the future.  We hope that funding can be identified to support scanning and reformatting the negatives and putting the images online.  Until then, temperatures should be cold enough for the negatives.

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