International projectionist (Jan-Dec 1949)

Questions and Answers on Safety Film THE appended questions and answers regarding Safety Film (the improved acetate stock known as High Acetyl Film which is now in circulation) was prepared by Eastman Kodak Co. for distribution among motion picture studio safety engineers. What is Safety Film? The American Standards Association defines Safety Film as follows: "Photographic films are classified as safetyphotographic film if they are difficult to ignite, slow-burning and low in nitrogen content. It defines in ASA Z38-3.1, 1943, the laboratory methods of test and analysis for determining whether a given film conforms with this standard. What is the Fire Hazard of Safety Film? Underwriters Laboratory, in its "List of Inspected Gas, Oil, and Miscellaneous Appliances," lists the various makes of Safety Film as "slow-burning" and states that the "fire hazard of these products in use and storage is judged to be of the same order as that presented by common newsprint paper in the same form and quantity." What is It Made of? The base is made by combining cotton or wood pulp with acetic acid, the acid found in vinegar. Propionic or butyric acids, which are very similar, are sometimes used in conjunction with the acetic acid. The products are called cellulose acetate, cellulose acetate-propionate, or cellulose acetate-butyrate. Will Safety Film Burn? Yes. Safety Film will burn if ignited with a match or other source of flame. Generally, it will go out of its own accord, but if it is in a loose pile it may hum almost as rapidly as paper. If It Burns, Why Call It Safety Film? The term "safety" is generally used in a comparative sense. When the old highwheeled bicycle was replaced by the modern bicycle, the latter was called a "safety" bicycle. It was obviously safer than the old "high-wheeler." Safety razors are so called not because one cannot cut oneself but because the danger of a bad cut is less than with the old straight razor. In the same way the term "safety film" has been used for a long time to differentiate the very much safer acetate film from the more dangerous nitrate film. What Hazards Does Safety Film Avoid? Safety film avoids the principal hazard of nitrate film. Nitrate film burns very rapidly indeed. When a roll is thoroughly ignited it cannot be extinguished with a fire extinguisher nor even by immersoin in a bucket of water. This is because it carries its own oxygen supply within itself in the form of the nitrate group. Nitrate film can be very easily ignited. Even a glowing cigarette can ignite it. When burning with a restricted supply of air, it gives off fumes which are extremely toxic. Safety film avoids all these hazards. Although Safety Film will burn, it burns very slowly. Generally, it will go out of itself unless it is piled loosely on the floor so as to be in a very favorable condition for burning. It can easily be put out by smothering it with water, or even by blowing it out. Does Safety Film Introduce Any New Hazards? Yes. It introduces the hazard of carelessness. This hazard will not be great until most nitrate film is replaced by Safety Film. When the time comes that nearly all pictures are on Safety Film, strict observance of regulations will be relaxed; usual precautions will not be taken. At that time an occasional reel of nitrate film may find its way into a projector that is not properly maintained, and a disastrous fire may occur. A portion of a reel of Safety Film may become damaged and a replacement be spliced in. The replacement might be on nitrate film. This reel might be run under projection conditions not suitable for nitrate film. The danger is obvious. What Are the Best Means to Avoid This Danger? Very few dangers are really bad if they are thoroughly recognized and understood. Constant attention, education, and publicity are the best safeguards. Does Safety Film Give Off Dangerous Gases When It Does Burn? The smoke given off by Safety Film when it burns or when it is roasted by an external source of heat is somewhat more irritating than ordinary wood smoke. It is not more dangerous than the smoke generated in ordinary types of fires. How Can You Tell Whether Film is Nitrate or Safety? The manufacturers print their company name together with the words "Safety Film" between the perforations and one edge of the film. This is not visible until the film is developed. Then it shows up in sharp black letters. Inexperienced people are often misled, however, because of the fact that in motion picture work images are transferred from one film to another. Thus the lettering that appeared on the negative film in black would appear on the positive in white. This makes it possible for the words "Safety Film" actually to be printed on nitrate film. The one sure test is the burning test. Can the Burning Test be Made Safely? Yes. It can be made safely but only if the right precautions are taken. The burning test should never be made in the same room where film is kept. It should never be made on film in a roll, or even on a large piece of film. A single frame should be cut from the roll. This piece of film should be taken to another room where there is no fire hazard. It should then be ignited with a match. Any one familiar with the way nitrate film burns can immediately tell whether it is nitrate or acetate. Nitrate film burns fiercely, while acetate film burns quietly and may even go out of itself. A glowing cigarette can burn a hole in acetate film without igniting it, while nitrate is almost always ignited. The new G-K 21 projector which is regarded in British technical circles as the "last word" in motion picture projection. Not a few of these units are now functioning in Canadian theatres. IP hopes to present soon a detailed description of this Kalee mechanism as compared directly with components of American projectors. 14 INTERNATIONAL PROJECTIONIST • September 1949