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PART" IV: BACKGROUND
1. NITRATE FILM
The motion pictures destroyed in the fire consisted of nitrocellulose film, a highly flammable substance akin to guncotton and long associated with film storage fires. Nitrocellulose film contains about 12 percent nitrogen but is not itself explosive; yet the burning characteristics can resemble a low order explosion.
Nitrocellulose was first used experimentally as roll film in 1889. It was used in the first commercial motion pictures as early as 1894, and it was the principal motion picture film base used by the film industry and United States Government until 1951 when it was last manufactured in the United States. Although fornns of safety acetate film had been available as early as 1909, it was not until after World War II that safety triacetate was manufactured with satisfactory physical properties for general theatrical use similar to that which nitrate film offered. Most of the motion picture film from the period 1894-1951 that is now considered valuable for artistic, historical, cultural, or other reasons was made on nitrocellulose film stock. Unfortunately, the flammability and chemical instability of nitrate film make it unsuitable as an archival record. The most feasible way to save the pictorial information recorded on nitrate film is to copy it onto safety film (triacetate or polyester), a program begun Ln NARS in the early 1950's.
Nitrate film's chemical instability and flammability are closely related. The inherent chemical instability of the nitrate base will eventually cause the film to decompose. This decomposition occurs in five stages: (1) discoloration; (2) tackiness; (3) softening, bubbling, and emitting a noxious odor; (4) welding into a solid nnass; and (5) degenerating into acrid brown powder. Nitrate film has a lifespan of roughly 60 years under good storage conditions. It is important to note that nitrate film can decompose from ane stage to another without igniting into flames. But as the film ages it beconnes more susceptible to self-ignition. The flashpoint of nitrate film in good condition is somewhere between 300 and 356 F, which is still very low when compared to 600 700 for paper. Nitrate film in advanced stages of decomposition may have a flashpoint as low as 106°F, according to National Bureau of Standards (NBS)