Vertical 35mm black and white film held in front of a bright window

In celebration of World Day for Audiovisual Heritage, the Media Preservation Unit at MSU Libraries would like to begin a blog series on the preservation efforts we are taking to steward a collection of nitrate film. This post is the first of six aimed at documenting the project of identifying and preserving these films.

In late March 2023, a colleague in the Library within the Vincent Voice Library reached out to Sarah Mainville, our Media Preservation Librarian, after discovering a handful of films tucked away at the top of a shelf. They wanted to determine whether the films could be cellulose nitrate.

History of Nitrate Film

Prior to the introduction of cellulose triacetate “safety” film in the late 1940s, 35mm motion picture film was primarily created with a nitrocellulose, or nitrate, film base. Nitrate film is highly flammable and very difficult to extinguish with traditional fire suppression equipment. This is mainly due how burning nitrate creates extreme temperatures as well as off-gassing oxygen as well as noxious gases. Since it creates its own oxygen during the burning, fire extinguishers and water-based fire suppression tools do not extinguish the flames. Many might recall the scene in Quentin Tarantino’s film Inglorious Basterds, where the theatre is quickly engulfed in flames from the projected nitrate film.The good news is that this film, if properly stored and monitored will not spontaneously combust, as previously believed. The National Archives and Record Management for the US has a fascinating blog post which discusses this point.

metal film can with old yellow label which reads Eastman Positive Nitrate Motion Picture Film
Metal film can from the Vincent Voice Library

Nitrate at MSU Libraries

After a series of texted images from our colleague, it became clear that we could not rule out the possibility that these films were nitrate. There were clues on the cans, as seen to the left, that at some point these films were either in the same collection as nitrate films, or were indeed nitrate themselves. Also, some of the films have NITRATE written on the edge of the film. You might think that this guarantees that the films is nitrate, however when nitrate films were duplicated onto safety film, the edge identification was also copied over. So, there are acetate films with NITRATE printed on the side. In order to be completely certain we needed to test each potential film through a burn test (more on this coming in future installments).

Due to the volatility of this film base, it was essential that we move them to cold storage while we prepare for the identification and condition assessment of the films. In the next installment of our nitrate film series, we will discuss why we use cold storage to stabilize the films, and how we quickly accomplished this to the best of our ability in the moment. Stay tuned!