How much does your collection weigh? – Part two

By Lisa Hennessey

In 2011, construction of Library and Archives Canada’s (LAC) new Nitrate Film Preservation Facility (NFPF) was complete. This building was constructed following the National Fire Protection Association’s Standard for the Storage and Handling of Cellulose Nitrate Film (NFPA 40) and, as such, LAC had to follow certain rules. One of these rules limits the total amount of nitrate film that can be housed in each fire-resistant storage compartment to 305 metres (1,000 feet).

The NFPA 40 guidelines speak in terms of length of film and were clearly written for motion picture film, this format being easily measured in metres or feet. Dealing in length of material is harder, however, when planning for the storage of nearly 600,000 still photographic negatives of various formats stored across 1,600 containers. How much is 305 metres when you are talking about a container full of 4×5 negatives? Instead, LAC decided to deal in weight. It was estimated that 305 metres of motion picture film represents approximately 4.5 kilograms (10 pounds) of nitrate. This would be our new maximum amount per compartment.

For the most part, LAC’s nitrate negatives are housed in paper envelopes (sometimes multiple negatives per envelope) and stored in cardboard containers. To determine the total weight of nitrate film per container the first step was to find out the weight of an empty container. LAC staff weighed an empty sample of each of the various container types found in the collection. We also weighed an empty sample of each size of envelope. Next, a survey team worked through the entire collection weighing each full container and then estimating the number of envelopes of each size inside. Once this was known, it was simply a matter of subtracting the weight of the physical container and the paper envelopes from the total weight, which resulted in a pretty good estimate of how much nitrate was in each container. Any container that was found to have more than 4.5 kilograms of nitrate film was rehoused in two containers.

A colour photograph of a woman wearing nitrile gloves and taking a negative out of an envelope. The table in front of her is full of envelopes and archival boxes.

Rehousing nitrate film in new containers

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How much does your collection weigh?

By Lisa Hennessey

This may not be a typical question faced by an archive or library, but it was a question Library and Archives Canada (LAC) had to answer back in 2009 when preparing to move its nitrate film collection to a new storage facility.

At first blush, the obvious solution to this question would be to bring in a scale and weigh all the boxes. However, in this particular case LAC needed to calculate only the weight of the nitrate film itself, not the weight of any containers, envelopes, film cans or albums. That was a challenge. How do you weigh a collection without actually weighing it?

LAC’s nitrate collection consists of 5,575 reels of film, dating from as early as 1912, and close to 600,000 still photographic negatives. From the early 1970s on, this material was stored at a facility on the Rockcliffe Air Base in Ottawa, Ontario. Built in the 1940s to house aerial photographic material produced by the Department of National Defence, the Rockcliffe building was showing its age by the late 1990s and a proposal was put forward to build a new storage building for the nitrate film. In 2011, construction on the new Nitrate Film Preservation Facility (NFPF) was completed.

A colour photograph of the entrance of a grey building with a row of yellow flowers in front.

The Nitrate Film Preservation Facility

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