Moving Picture Age (Jan-Dec 1922)

MECHANICS o/VISUALIZATION A Department Conducted by AUSTIN C. LESCARBOURA, SSifflmelan In this department appear each month discussions of the important materials of visual instruction — projectors, films, stereopticons, slides, screens, cameras, lenses, and other items of equipment on which the non-theatrical exhibitor should possess authoritative and impartial information. It should be distinctly understood that all expressions of opinion emanate from Mr. Lescarboura, and that Moving Picture Age takes no stand upon the opinions expressed in this department. THE QUESTION OF FILMS HISTORY is repeating itself in the motion-picture industry. Go back to the pioneer days of the industry and you find the different inventors and producers of motion pictures, such as they were, using various sizes of film. These sizes ran all the way from the wide films of the Bioscope, which had frames fully as large as the average amateur snapshot, to the Edison film, which finally became the standard the world over. Today we have at least two standard sizes, namely, the professional standard and the somewhat smaller safety standard ; and we must soon count at least a third standard of still smaller dimensions, especially suited to certain portable applications and for home use. The Professional Standard Film The professional standard, which is the direct descendent of the pioneer Edison Kinetoscope film, was finally adopted as the standard of the world because it combines economy of film with a maximum screen effectiveness. A smaller film could not be used with such good results in conjunction with a large-sized screen, because the degree of magnification would be too great and the projected image would therefore lose much in clearness. Indeed, the writer has been told by old-timers that the screen results obtained with the old Bioscope films were simply remarkable — far ahead of anything that is being achieved today — because of the larger film images and the subsequent lower degree of magnification. But if we were to increase the size of the present professional film, the added cost of film would be so great as to be absolutely prohibitive. Hence we have had to compromise between good screen results and a minimum cost for film, and the answer is the present professional standard. 7 What problems are handicapping you in your visual in• str uction work? Mr. Lescarboura stands ready to answer by correspondence the questions of any subscriber pertaining to equipment, when the inquiry is addressed to him at the office of Moving Picture __ Age and is accom *W panied by stamped, I addressed envelope • — The Editor. Its Composition and Hazards The usual professional standard film has a celluloid base, or, to use the language of the chemist, it is made from nitro-cellulose stock. This material is little different from guncotton, and as such it is of course highly inflammable. ' Still, there is no reason why the careful operator should have any trouble with celluloid film. Our leading theatres handle rnile after mile of film each working day, yet never experience any trouble with the highly inflammable material they are handling. Celluloid film will not blaze up by itself ; a flame or intense heat must be applied for a period sufficient to start a blaze. The majority of projectors today are so designed as to reduce the fire hazard to an absolute minimum, being equipped with such safeguards as automatic shutters which drop down in the path of the source of light when the speed of the machine drops below a predetermined point, fireproof magazines which hold the film reels, and fireproof traps through which the film passes in and out of the magazines. At worst only a few feet of film, which happens to be exposed between the upper and lower magazines of the usual projector, can burn, causing little or no damage. Comparative widths of safety standard and standard film The greatest hazard connected with the use of inflammable films is while the films are not in actual use. The inveterate smoker is a positive nuisance where films are being unpacked, examined, rewound, or otherwise handled. In fact, film should always be kept in cans until it is actually about to be placed in the projector. There is no excuse for having a film fire if ordinary care is exercised. Of course it cannot be denied that there must be a certain sense of security that goes with slow-burning film. Such film is made of an acetate-of-cellulose stock which, unlike celluloid, burns quite slowly if at all. If a match or great heat is applied to celluloid, it immediately flares up with a hot, rapid flame. The slow-burning stock, on the other hand, begins to burn if one is sufficiently persistent, and then only with a weak and lazy flame which generally dies out as soon as the source of fire'is removed from the stock. The Slow-Burning Film Of late years manufacturers of motion-picture film, which is known as raw stock in the blank condition, have turned their attention towards acetate-of-cellulose or slow-burning film. Today the professional standard film is obtainable in slow-burning stock, so that the nontheatrical exhibitor can use slow-burning films in any standard projector or portable projector with absolute safety. Such film is somewhat more costly than the celluloid stock, but more and more producers are turning to such film for educational and other non-theatrical reels to be used under conditions far from being as safe as those in the average theatre. In fact the motion-picture industry in general is of the opinion that in time celluloid must go. It may not be next year or five years from now, for a heavy investment is represented by the millions upon millions of feet of celluloid film now in general circulation ; but eventually all films will be of the slow-burning variety, even though such film is more costly, thus eliminating all possible source of danger from both nonprofessional and professional exhibitions. All of which brings us down to another standard, known as the safety standard. It was the introduction of acetate-of-cellulose film in France that brought about the demand for another standard. When this new stock was introduced, it was at once evident that it would make motion pictures safe anywhere and in the hands of anyone. However, in order that there might be no confounding of celluloid and slow-burning films it was obvious that the latter would have to be of a different size and possibly of a characteristic perforation, and, by patenting such perforation, it would be possible to identify the film at all times. This new film became the Pathescope film, which was introduced in this country some seven }'ears ago. Realizing the need for a slow-burning film, especially in the home, the Society of Motion Picture Engineers some three years ago accepted the Pathescope width, but changed the characteristic perforation to a uniform perforation, which was not patented and which was therefore open to all manufacturers. This size became 16