The Bioscope (Mar-June 1914)

THE BIosScoPE, APRIL 30, 1914. THE PROJECTOR AND THE FILM. SOME POINTS IN PROJECTOR CONSTRUCTION AND MANIPULATION AFFECTING THE LIFE OF THE FILM. By JAMES W. BARBER, A.M.LE.E. The life of the cinematograph film should be the concern of everyone engaged in the business. It is an unfortunate fact that, whereas considerable advance has been made during recent vears in the photographic and artistic qualities of the finished film, little improvement has bzen made in regard to those details of projector construction that make for long life and minimum wear and tear of the film. In point of fact, it must be admitted that in spite of all the advances made, the life of the modern film is shorter than that of the film in use six or eight years ago. Probably the introduction of film hiring has had most to do with the rapid destruction of films, although the era of continuous performances, in which in many cases the object of the management is to rush the films through at all possible speed to make room for a waiting public has had no small bearing on the wear of the film. In days gone by, when a man purchased a film for his own use he took great care in its handling; he selected a projector whose function was limited to that of projecting, and not of film mangling. He chose his operator not on a basis of ‘in how many seconds can you thread up and what length of film can you put through per hour?’’ No! the proprietor of that day chose both his mechanical plant and operating staff with a view, in addition to projection, te minimising the wear of his film. To-day it is an unfortunate fact that the average user sees no further than three days ahead. Provided a fair show be given during the thre2 days the film is being shown at his theatre, the condition when it leaves is of little, if of any, concern to him. An operator, when he is engaged, is never questioned as to his capabilities in the care and hadling of the film, but only on his what one might call screen handling powers. A projector, when it is purchased, is not chosen from the point of view of life of film, but only that of steady and flickerless projection. Not that flickerless and steady projection nezd not go hand-in-hand with minimum wear and tear of film. On the contrary, it should be the case that the manufacturer who has considered all the little details in projector construction. that make for minimum wear and tear, and there for long hfe of film-has long ago mastered the more el@imemaryy ¢ (iced [ ling points of steady and pleasing projec&dn. What are the principal factors that make for longevity of film? The factors can be placed broadly under the headings of (1) the projector element and (2) the human el2ment. Dealing with the projector element first, those factors that make for scratches on the emulsion and celluloid surfaces of the film are patent to all, as are likewise their results on projection, ‘rain’ being an abomination with which everyone is acquainted. Another factor, however, more subtle in its causes, but very apparent in its results, are those conditions that make for weakness at the sides of the picture, and which weakening the edges of the sprocket holes and the sides of the film, soon cause permanently unsteady projection and ultimate tearing of the sprocket holes. ‘Rain’ on the surface of a film, regrettable enough though its presence be, can to a great extent be removed by a process of cleaning, but wear at the sides of the film 1s practically irremediable. Undoubtedly the chief factor causing damage to the sides of the film is due to mal-design or mal-adjustment of the bearing roller or rollers of the sprockets. What is the function of the bearing roller? To prevent the film leaving the Fim BEARING ROLLER FIG. 1. teeth of a sprocket. Now, the actual depth of tooth is considerably greater than the thickness of the film, and no good purpose can be served by pressing the film unduly on the drum of the sprocket wheel, when all required is that the film should be,held:-se, that the teeth engage in the sprocket, |heles., | -Yetpwhat, do we find? Some machines are so constructed that the only