International projectionist (Jan 1961-Dec 1962)

they are not valuable they should be disposed of promptly by the means suggested at the end of this article. Fire Hazard The fire hazard of nitrate film has often been described. (2.145) jrvery0ne should remember that nitrate film is a close cousin to gun cotton which is used in high explosives. Nitrate film: 1. Ignites easily, often spontaneously. 2. Burns rapidly and violently, even without air. 3. Causes explosions under some conditions. 4. Produces large amounts of very poisonous gases. 5. Is very difficult to extinguish once ignited. Nitrate film can be ignited by contact with a hot light bulb or radiator. Spontaneous combustion can result from storage in warm weather, particularly under an uninsulated roof. Nitrate film also decomposes spontaneously with age, especially under warm, damp conditions. C6' 7) Deteriorated nitrate film is more likely to ignite spontaneously than good film. Deterioration can be detected by the characteristic odor of nitric acid, yellow discoloration, sticking, brittleness, and in advanced stages, the formation of a hard "froth" or brown powder on the film. (Figure 1) . Once ignited, nitrate film burns with tremendous speed and violence. A single roll of film becomes a large flaming mass in a few seconds ( Figure 2 ) . A small storage room full of nitrate film, if ignited and not protected with automatic water sprinklers, can shoot a massive flame 20 feet high for a distance of over 100 feet ( Figure 3 ) . The magnitude of the fire depends only on the quantity of film involved. Nitrate film will burn even in the absence of air, because it already contains sufficient oxygen internally. Such a fire cannot be extinguished by smothering, but only by an immediate deluge of large quantities of water; hence the importance of automatic water sprinklers in nitrate film areas. If nitrate film becomes ignited in a confined space not provided with a vent, the gases formed often explode with great violence. Vault doors can be blown off and roof or walls blown out. A roll of nitrate motion picture film thrown in an incinerator can blow off the door. Even though nitrate film does not detonate on impact, it should be treated with the same respect as explosives. Finally, burning nitrate film gives off large quantities of thick yellow nitrogen oxide gases ( Figure 4 ) , particularly where the air supply is restricted. These gases are approximately ten times as poisonous as carbon monoxide (6) and have frequently been the cause of deaths. Film Identification The first precaution in preventing accidents with nitrate motion picture film is to clearly identify it and separate it from the more common safety film. Identification is not always as easy as it might seem. Although most processed motion picture films carry the words Safety or Nitrate printed along the edge of the film, there are exceptions. It is also possible for the word Safety to have been printed from a safety master positive or duplicate negative onto a nitrate print. The only safe rule to follow is: Unless the film is clearly identified as safety film beyond question, assume that it is nitrate until proven otherwise. Another important point to remember is that a roll of Please turn to oage 17 ternational Projectionist May 1962 Figure 1. Nitrate motion picture film in various stages of decomposition. A. Image faded out and emulsion sticky. B. Hard "froth" on side of roll. C. Partially decomposed to brown powder.