The Explosive Films

For several decades, much of world cinema was recorded on film capable of spontaneously combusting. The cellulose nitrate used in early films produced images of exceptional quality, but it was also extremely unstable. Some film archive fires spread so fast the reels seemed to explode almost instantly.

Until the mid-20th century, cinema massively used cellulose nitrate film, inherited from 19th-century research on guncotton and nitrated explosives. The material had everything going for it—flexible and thin, with remarkable image quality—but it had a formidable defect: heat, time, or slow chemical degradation made it extremely flammable. Terrifyingly, nitrate film releases its own oxygen when burning, so that some reels continue burning even partially submerged.

Archives were the first victims. Stored in hot or poorly ventilated premises, reels decomposed, released acid gases, then ignited, and several fires destroyed thousands of films over the century. The most dramatic occurred in 1937 in Fox's New Jersey warehouses, where most of the studio's silent films disappeared. Theaters weren't spared: the projector lamp heated the film intensely, and a blockage sometimes sufficed to cause instant combustion.

The paradox is that cinema historians recognize nitrate prints as having luminous depth superior to many later formats. It's this particular texture that some current restorations strive to recover, digitally simulating the brilliance of old projections.