International projectionist (Jan-Dec 1955)

1945 to 1955: Ten Years of Progress In Projection Technology THE PAST ten years have witnessed a number of important developments in 35-mm film projection, and also in the complicated photographic and electrical processes that go into producing a finished motion picture release print. A few of these developments, such as 3-D and CinemaScope, are immediately recognized by the moviegoing public, hence possess direct boxoffice value. Other innovations, such as the reduction of ground noise by magnetic recording, the reduction of negative-emulsion grain by the VistaVision process, and the improvement of image resolution in color prints by the use of multilayer dye-coupler color positives, are holding satisfaction with theatre motion pictures at high levels by virtue of their influence on visual and sound quality. Another important development, the substitution of safety film for the dangerous nitrate film of yesteryear, is of greater significance to projectionists than to the general public. The average projectionist has never had a film fire in his projection room, but he knows of c<:ses where brother projectionists have been seriously injured, or even killed, by accidents with nitrate film. All theatre-release prints were made f.n nitrate-base stock until 1946, when triacetate safety base began to be produced on a large scale. The fireproof construction of projection rooms and projection equipment is a sufficient reminder of the days when movie projection was classed among the more hazardous occupations. Projectors and projection rooms are still equipped with such safety devices as were considered necessary for nitrate-film projection. Unfortunately, the use of nitrate prints has never been outlawed. For this reason, every possible safeguard against film fire still must be installed and kept in good working order. Sooner or later, however, nitrate prints will be a thing oi the past, and the projectionist will find himself less likely to be injured by fire than any other theatrical employee. Safety Film Advantages The prevalent belief that triacetate safety film presents a fire hazard, albeit a small one, is wrong. Safety film is technically "slow-burning" insofar as it is physically possible to ignite a strip cf it and keep it burning by guarding the feeble flame against drafts which In addition to widely-heralded developments in wide-screen projection, stereophonic sound and slow-burning triacetate film, the last ten years have seen a number of little-publicized but important improvements in projection methods. would extinguish it. But to maintain the combustion of a large roll of safety film is extremely difficult without some other source of flame. To burn up a reel of triacetate film in the closed magazine of a projector is presumably impossible. The writer does not know of a single case where njiybody, by design or otherwise, has succeeded in burning more than a couple of inches of safety film in a motion-picture projector. When the first theatre releases on triacetate-base film appeared, many projectionists were made aware of the difference in film stock by the failure of fiJm splices to hold together. This was especially true when "sneak tests" of the new safety film were conducted in 1946. Alternate reels of certain feature films were printed on the new safety film, and no one took the trouble to tell the projectionist that his regular cement was unsuitable for splicing the new stock. A few "shorts" were also issued on safetybase stock in 1946. These sent wise projectionists hurrying to the nearest drug store for glacial acetic acid, a corrosive and pungent liquid capable of joining tiiacetate film, especially when a little chloroform was added. In 1947 came the first regular safetyfilm releases in the form of Republic's ' duplitized" (double-coated) Trucolor productions. The new safety-film prints arrived at theatres unaccompanied by either adequate film cements or instruc tions for splicing. In the meantime, however, manufacturers of film cements were quietly switching over to different splicing ingredients, but that was no help to projectionists who possessed l^rge quantities of nitrate-film cement. The use of an unfamiliar type of film base was bad enough, and the doublecoated color film only made matters worse. This was the severest test to which the new safety film could have been subjected; surprisingly, it emerged victorious. Examination of used Trucolor prints by film technologists revealed that the new safety base did not become brittle or shrink like nitrate film, and that it withstood wear and tear remarkably well. New Film Cements Necessary Years of experience with nitrate film h.ive accustomed projectionists to strong splices quickly made. Nitrate base is leadily attacked by a large number of rather common organic solvents which may be used either singly or in combination in film-joining fluids. Nearly all of the commercial nitrate-film cements contained a large proportion of acetone; most contained small amounts of amyl acetate (banana oil), ethyl acetate, or some similar compound; the cheaper cements were composed mainly of alcohol and ether, ingredients which work well only in combination, and all were thickened to the viscosity of thin MELE KAMKIMAKA (MERRY CHRISTMAS) HAUOLI MAKAHIKI HOU (HAPPY NEW YEAR) LOCAL 665 HONOLULU HAWAII INTERNATIONAL PROJECTIONIST • DECEMBER 1955 21