Motion Picture News (Nov-Dec 1925)

2586 Motion Picture News Projection Y^m^u^^ Ideas <§ a^o§ Inquiries and Comments Standardized Screen Brightness Part I HE society of Motion Picture Engineers, not so very long ago, took the first important step toward achieving something which long has been sorely needed in the motion picture field — the standardization of screen brightness in the motion picture theatre. The Society appointed a committee to investigate the possibilities of bringing abo.it the desired conditions, but like many othei first efforts, little success attended them since the committee reported back that because of the many variables involved it would prove extremely difficult, if not altogether impossible, to attain a standard screen brightness in any true sense of the word. Let us hope, however, for the general good of the motion picture industry at large and in the interests of public welfare, that the Society of Motion Picture Engineers, will in no way relax its efforts to bring about a successful termination to its investigations. Wasteful and Dangerous We say for the motion picture industry at large and the general public welfare for the simple reason that the present chaotic* conditions in the average run of better theatres is highly wasteful to producer and exhibitor alike and highly dangerous to the visual welfare of the theatre-going public. The producing end pays the cost in the way of short-lived film, thereby resulting in higher rentals, at the same time involving a sheer waste of income earning film. Part of this resultant increased cost is undoubtedly passed on to the exhibitor but it is not always possible, nor even feasible for thit matter, to make up the loss in this manner. Then, too it is obviously unfair to penalize all exhibitors alike for something which only a few renters may be responsible for. We use the word few reservedly since it is our firm belief that the average better theatre in this country uses considerably more light for screen illumination purposes than is actually required for continued safe vision. (This does not hold true for the average small town house.) The mere fact that only the worst cases are exposed, due to the pronouncedly visible harm they do, is not proof, by any means, that the danger is confined to these instances alone. The only difference between these and the milder offenders lies in the fact that the one is readily apparent while the other is not. The final result, however, is inescapably the same — film scrapped long before its time. Aware of the Fact That the producing end of the industry is fully aware of the waste in film thus resulting is easily seen. Slowly but surely efforts are being directed toward the end of jacking up exhibitors in the way of using means to conserve the film. Periodic inspections of projectors have long been in vogue in certain localities and educational efforts are now under way to reduce the evils of excessive screen brightness. The producing organizations taking their cue from the S.M.P.E., are becoming increasingly active in their efforts to restrict this ever growing evil. A Growing Danger In this matter of film waste due to its excessive illumination grave concern seems to be felt over the indiscriminate use of the high intensity arc in houses where they are not actually needed. Not only does this light source possess extreme brilliancy but the quality of its color is such as to modify the resultant color of projected tinted film This color has been attacked with the object of removing it but so far unsuccessfully. The high intensity arc, however, is not done responsible for this depreciation in film condition. From this country, Canada and European countries we have received direct reports that the concentration of heat at the aperture resulting from use of other types of arc is receiving serious attention and one English company has placed on the market a form of heat absorbing glass to be used in connection therewith. The reason for this should be evident. Tn this matter of light projection anything that involves light must, by the same token, involve heat. The two are inseparable and ro "cold" light has, as yet been invented. Furthermore, it can be said that any increase in light is also attended by a corresponding increase in heat as far as projection is concerned. Thus, doubling the amount of light passing through the aperture is pretty certain to result in doubling the amount of heat radiated through the aperture. DUPLEX Measuring Machine PLUS POSTAGE Duplex My ion Piclure In J us Ties, Inc., Long Island Cily; N. V ■ When, in addition, the lesser absorption of heat energy, due to the absence of condenser . lenses in some systems is considered, it is small wonder that the spot on the aperture is more intense than with the old form of arc. This is not the principal factor, however; there is a more serious one. The reflector arc is highly efficient. It gives the same screen illumination as the most powerful D.C. ordinary arc at one-third to onefourth the cost of operation. Herein lies the danger. With the old condenser form of arc the exhibitor was not prone to use any more amperage than was required for satisfactory screen results. If anything, there was a tendency to use less because of the large bills for power which acted as a check upon his "over shooting" proclivities. Now, however, every exhibitor, large or small has it within his means to get the equivalent of a high powered arc at a fraction of his former operating expense. The fact that he can secure lower amperage sizes of reflector arcs means little since the differential in operating costs between the various amperages is, after all, relatively small. There is a lower limit below which any reduction in operating costs becomes of little importance. Here to Stay The wide spread use of the reflector arc — and it will be widespread — will result in one of two things, either a clamor for standardization screen brightness or the use of heat absorbing glass. For that matter, both appear to be desirable. The reflector arc is here to stay. Any device which does the work of its predecessor at one-fourth the cost is not lightly to be tossed aside. Something of the kind has long been needed in the exhibiting field as the old arc was grossly inefficient. We expect a prosperous future as far as the reflector arc is concerned. The manufacturers obviously are not concerned with the problem of film deterioration as long as their product does not involve greater danger from film fires. The danger with this device is rio greater for that matter, than with others. The exhibitor on the other hand is equally unconcerned in this matter since he is effecting great savings in operating costs. The burden of it appears to fall upon the producers. They seem to realize it and are preparing to meet it. Film deterioration, aside from mechanical injury, is due to just one thing; that is, passing too much radiated energy in the form of light and heat, through it when at the aperture plane. It makes no difference whether this light is used to illuminate a picture at a distance of 50 feet or 300 feet the effect is the same. On short "throws," however, a much lower intensity of light (beam candlepower. if you (Continued on p&ge 2589)