Movietone Bulletin (September 1928)

A Matter of Definition ROM New Brunswick, N. J., comes this letter: “Dear Mr. Richardson: Reading your answers to projectionists in the Bulletin, am hoping you can help me. My trouble is poor focus. Bausch & Lomb projection lenses, half size. Lenses 7144 E. F. When I focus picture some part of it is always ‘out.’ It may be at bottom, sides or at top. If I set the top and bottom in focus, then the center is out. It is not the film, because I have a special piece of mica for focusing and it does the same thing. Using Peerless lamps and Westinghouse generator equipment. Very hard to get a bright picture on the screen.” If this good brother has set the matter forth correctly, the trouble is either in the projector aperture or in the projection lens; probably the former. Examine the aperture plate closely. If its film tracks are worn perceptibly—not perfectly flat when tested with a steel straight edge—then a new aperture plate and tension shoes should effect a remedy. If these are in good condition, then something is wrong with your lenses, but that seems rather unlikely. Since you apparently can focus both top and bottom of the screen image sharply, the trouble is not due to projection angle. Worn aperture plate and shoes are the seat of the trouble, I think. As to light, are you sure you have your optical system properly lined? If your generator is producing the right amperage, and you are using sufficient current, (can’t even guess what you ought to use, as I have no data as to picture size or character and condition of screen surface), then the trouble lies in your optical system. System out of line or dirty lenses would affect screen illumination; also distance of rear surface of projection lens from film—working distance of projection lens it is called. I would strongly advise this brother to secure a copy of the Bluebook of Projection and study up on such matters. Also be it remarked that in my answer I am depending upon the correctness of the data supplied. If the focus could not be made sharp at both bottom and top, but either could be made sharp separately, then the answer would be too much projection lens free diameter for the projection angle. If it could be made sharp all over, except at one point, then probably it is a spot of oil on the projcetion lens surface, a finger mark or, (it has been known), a bit of transparent film adhering to rear surface of lens. If when the center is out at the top, bottom and sides are sharp, and vice versa, then the film does -not lie perfectly flat over the aper ture, probably for the reason before set forth—that or buckled film, and it certainly is not the latter in this case. Positions Not Available The editor is in receipt of many letters asking whether there are not positions for projectionists available in the Western Electric Company installation forces or in movietone. Some of these letters come from projectionists of undoubted high character and ability —men whom I would really be more than pleased to do anything within my power to advance. However, gentlemen, I am sorry to say that while it is quite true that a few—a very few—projectionists have been found available for the Western Electric engineering force, the chance is so slight that it is hardly worth considering; moreover, such positions are not nearly as desirable as they may seem to you. Almost the entire field force is selected from men who might qualify with little trouble as radio engineers of high attainment. Even they must pass muster in a class which is put through a_ course which I can testify would put a few crimps in almost any one’s brain. You can’t always judge by appearances. A jackass has long ears but he can’t hear any better than anybody else. Circumstances alter cases. That is all right, of course, except when it is a case of Scotch. | FLICKERS The world is a pretty good judge of ability. As soon as a fellow gets big enough for people to watch his smoke some cigarette company grabs him for an ad. They say you can’t believe anything you hear. But you can believe what you hear from movietone if it is projected right. They ‘say you shouldn’t trouble till trouble troubles you. But it pays to trouble mechanical trouble before it gets to troubling you. Not all games will work both ways. You never heard of a man mortgaging his automobile to make a payment on his home. A lot of fellows think the best way to hold a job is to sit down on it. A lot of people’s judgment ought to be in good shape. They never use it. (Continued from Page 1, Col. 3) faults in one issue of the Bulletin. I therefore will take the liberty of continuing our conversation through enough issues to enable us to cover the subject competently. First of all, it is of large importance that the center of the mirror, if one there be, the condenser, if one there be, the projector aperture opening and both the front and rear end of the projection lens be exactly on the optical axis of the system. And when I say “exactly,” that is precisely what is meant. Unless this be the condition you are not working efficiently. This is especially true if the light source be Mazda. If the center of the Mazda filament be even so little as one-sixteenth of an inch off center—off the optical axis— the loss of light will be very great indeed. The projectionist who works carefully and efficiently will make periodic and not too infrequent tests and know that the entire optical systems of his motion picture projectors are exactly in line. (Continued in next issue.)