Exhibitors Herald World (Oct-Dec 1930)

52 Better Theatres Section November 22, 1930 CONTINUOUS PERFORMANCEDAILY All ladder-work around your theatre becomes an uninterrupted schedule of efficiency, performed swiftly, completed on time, if your employees work from the Dayton Safety Ladder. It speeds up the job by keeping the fellow who's doing the job confident of safety wherever he's working. It eliminates risks. Wide leg-spread, straight back, sturdy, steel-braced construction, large, guarded platform — these are Dayton Safety Ladder features which insure safety. Made in sizes 3 to 16 feet. Moderately priced. Type "B" Dayton Ladder is a smaller, popular-priced safety ladder for all purposes. Seven sizes. Write Dept. BT11 for full information The Dayton Safety Ladder Company 121-123 W. Third St. Cincinnati, Ohio BAYTON Safety Ladder (Patented) Stork carried on Pacific Coast by E. D. Milliard Co., Los Angeles and San Francisco, and by 16'i Other distributors from coast to coast. Made and distributed in Canada by Percy Hermanl, Ltd., Toronto. Certainly the heads of producing corporations do not wish faulty prints to be released. It is not in the nature of things that they should, but they are at the mercy of employes, and employes are not always what they should be. I suggest that each print be marked with some number, or in some other way, and that projectionists be invitea to report to the producing corporation any faults found in the print. This would give the producer a chance to check up, ascertain exactly what employe is responsible for the print being sent out in faulty condition, and supply means for eliminating carelessness. WANTED: A STEPLESS FADER ONE of the really big faults found in sound technique in theatres is lack of means for sensitive control of volume. The "steps" in all the faders now in use are altogether too great. Many times the sound is too loud simply for the reason that if the next step were used it would be too low, or vice versa. The thing that is needed is a stepless fader, and I believe such an instrument can be made. The two projectionists in British Columbia, referred to in a previous article, are using a device involving the "stepless" principle in connection with their monitoring horn. Even if the engineers cannot devise some scheme for a stepless fader, they certainly can increase the number of present resistance units so that there will be many more steps. Of course such an instrument would be larger and some what more expensive, but as I have before said, the issue is not what the instrument costs (within reason, of course), but the relative excellence of the results produced. And certainly every projectionist will tell the engineer that better results would be produced if there were either no jumps at all, or less extensive ones. I have many times sat in theatres and observed the projectionist produce decided jumps in volume in an endeavor to make up his mind which was best, the one above or the one below. Certainly that is not a pleasant effect, and the projectionist receives blame for something that is beyond his control. May I suggest to the sound engineers that among the improvements in sound equipment to be made, stepless fader should be listed? INSUFFICIENT SCREEN ILLUMINATION BEN BRINCK of West Point, la., writes, "In one of my theatres I am having difficulty in securing sufficient screen illumination. At this particular theatre the projection distance is 47 feet. Am using a silver screen. The light source is a 900-watt mazda lamp. The projection lens is 2% inches EF. It is an old lens and I am wondering if the trouble doesn't lie in it. I can get plenty of light to the aperture plate, but beyond that it seems to get lost. Thought possibly if I would get a pair of Cinephor lenses it might cure the trouble. However, I will let you solve the matter for me." As to getting plenty of light to the aperture plate, and not enough beyond it, the trouble would seem to lie in one of two sources; first, size of the spot; second, the diameter of the light beam at the point where it meets the lens with relation to the diameter of the projection lens itself. Light is lost with rather amazing rapidity as the diameter of the spot is increased. I haven't the figures with me, but as I remember it, with an inch-anda-half spot — that is to say, a spot one and one-half inches in diameter — something in excess of 50% of the light is lost. However, that applies only to the arc light source. The mazda light source spot is very different. I am 3,000 miles from my office and have not the "dope" on that particular thing available. But regardless of what the light source may be, the spot should be kept just as small as it is possible to keep it and have pure white light on the screen. As to the diameter of the light beam where it meets the lens, draw a black circle of equal diameter with the free diameter of the rear lens of your projection lens on ordinary white writing paper. Measure the distance of the aperture from the rear surface of your projection lens when the picture is in focus on the screen. Remove the projection lens and hold the paper a distance from the aperture exactly equal to the distance the lens was from the aperture. Block the fire shutter up, light your mazda and looking in through the hole where the lens was. You can instantly see whether or not all the light enters the lens. If the light beam has equal or less diameter than the black circle, then there is no light loss there. If the contrary condition obtains, then there is light loss, and you need a lens of larger diameter. I am glad to have projectionists troubles left to me, as Brother Brinck puts it, but just now I am not as able as I should be to give those troubles proper attention. This traveling around the country (as I have been doing all summer, lecturing before projection organizations), hasn't given me the time and the materials to be thorough. However, it won't be long now, for I am back to the place I shall, for the time being, at least, call home and shall be properly equipped to serve you.