Stability of Motion Picture Film
The type of film support - polyester, cellulose acetate, or cellulose nitrate - is critical for the long-term preservation of motion picture film. For detailed information, please visit Film Based Negatives and Positives.
Polyester motion picture film predominates after 1990. It is very stable when stored in moderate temperature and relative humidity conditions.
Cellulose acetate film is susceptible to acidic deterioration called “vinegar syndrome.”
- If resources allow, assess the degree of vinegar syndrome using A-D Strips (acid detection strips). Discuss testing with a preservation specialist; it may be feasible to test a representative sample of a collection with multiple films.
- Store any deteriorating cellulose acetate film in metal or polypropylene plastic cans and isolate it to prevent damage to other titles.
- While cold temperatures will extend the life of any cellulose acetate film, it is especially important for preserving films with vinegar syndrome and for highly significant, important titles. Refer to these pages on Film-Based Negatives and Positives and Cold Storage for more information on acetate film and cold storage.
Cellulose nitrate was the predominant film base from the 1890s until the 1920s, and was produced until the early 1950s. It should be considered unstable and may deteriorate rapidly in non-climate-controlled conditions. It poses a fire risk when stored improperly.
- Address any cellulose nitrate film as quickly as possible. While cold temperatures may slow cellulose nitrate deterioration, the film will remain unstable.
- Follow guidelines in NFPA 40 Standard for the Storage and Handling of Cellulose Nitrate Film (National Fire Protection Association).
- Isolate any cellulose nitrate motion picture film from the rest of the collection. As per NFPA 40, store nitrate motion picture film in metal cans and do not exceed 1000 feet of film per can.
- Store the film in cool, dry conditions only until a suitable plan of action can be developed and carried out.
- Nitrate motion picture film should be duplicated by a knowledgeable company and the original deposited with an institution capable of storing nitrate. If this is not possible, it should be disposed of according to federal regulations.
- Contact a conservator or a motion picture preservation specialist for additional guidance if you have cellulose nitrate in your collection.
Cold storage in temperatures of 35°F or lower is critical in preserving cellulose nitrate and cellulose acetate motion picture films, and is recommended for color films.
Consider storing deteriorated motion picture film, especially if highly significant, in even colder temperatures below 30°F.
Film Inspection
A film preservation specialist examines a 16mm film using a film calculator that measures the length of the footage.
