Movietone Bulletin (July 1928)

injury to results. It is one of the duties of the movietone projectionist. See that you attend to it! > Film Pick-up Amplifier HIS week two projectionists, y hae in Maine and one in Texas, have asked for the same informa tion, It is this: “Will you explain just what the purpose of the film pick-up amplifier is? By this I mean the one attached to the projector,” If you would study your instruction book I think you would understand, though perhaps a bit of amplification on what is therein set forth under “Film Pick-Up Amplifier” would not come amiss. The film pick-up amplifier, which is the one asked about, is mounted on the projector at the front of the film reproduction attachment. Its office is to amplify the electric impulses or current which comes from the photo-electric cell. It is what might be termed the first stage of amplification as between the film and the horn. The reason for amplification at this point is that the impulses coming from the photo-electric cell are weak, and if the first stage of amplification were at the main amplifier, which is usually some distance from the projector, there would be likelihood of induced currents being picked up from AC_ currents, switches, commutators, etc. This would occur on account of the circuit from the photo-electric cell, over to the main amplifier, acting like a radio antenna in picking up any electrical disturbances in the neighborhood. All circuits act in this manner to some extent unless very special precautions are taken. These interference currents would then be amplified along with the sound current from the photo-electric cell. The result would be noise in the sound projector horns. To avoid this the sound impulses are amplified at the projector to a degree sufficient to the make the interference currents insignificant by comparison; then the further amplification given by the main amplifier, while sufficient to enable the sound current to operate the sound projectors, does not have to be so great as to cause the interference effects to be audible. There are three tubes and three stages of amplification. Each of the tubes is a Western Electric 239-A vacuum tube. The tubes are mounted on a spring suspension, as you are told in the instruction book, in order that they be not affected by the vibration of the projector. On the door of the compartment housing the tubes is mounted a control for regulating the current passing through the tube filaments and a meter which measures this current. I cannot too strongly urge that you study the instruction book. If you come across anything therein which is not clear to you, advise me and through the Bulletin the matter will be made clear to you. Watch the Lights! Remember, men, that the auditorium lighting has much to do with your screen image—its excellence I mean, of course. Especially is this true of the lights and the decorations near the screen. If you are a real motion picture projectionist you will be interested, and deeply interested, too, in anything which affects the beauty of the picture on the screen. You will therefore study the matter of auditorium lighting, screen borders and surroundings. You will put yourself in position to talk to your manager intelligently and authoritatively upon such subjects. By so doing you will increase his respect for you and your work. It is just this difference which marks the dividing line between the motion picture projectionist and the machine operator or attendant. The former studies his business and treats it as a profession. He respects his work. He is interested in it. He does not regard his work as merely a necessary nuisance and a thing to make a living with. He regards the operation of the projector (machine) as merely one relatively small item in motion picture projection, the really big problems of which are purely optical. Which are you, brother? A “machine operator” or a motion picture projectionist? There is a vast difference. A rewinder is a little like a rookie—you have to watch the darn thing to be sure it is in line. | FLICKERS | Projectionist Pete is going around with a furrowed brow these days. No, it is not trouble—exactly. The fact is that he is deep in thought. Movietone is the indirect cause of it. To be more specific, the fader is the cause of it. Pete was deeply intrigued by that delicate and mysterious mechanism which controls the volume of sound. And Pete, being of an inventive turn of mind and being deeply intrigued by the fader which controls sound volume, was inspired with an idea, His idea is to invent one to put on the baby. Dumb Dolly, unctuous and untutored usherette in a Broadway movie house, was all tired out the other day. The head usher had her looking all over the place for the acoustics. She finally came back and reported somebody must have stolen them. Great events cast their shadows all around them.~ We have it on authority that since companionate marriage was invented, a certain projectionist, who is an ardent companionate champion, can’t make a satisfactory film splice. If hot weather and projection booths and love affairs take something vital out of you go to the “Cupid Cobbler” on one of the daily papers. Her business is halfsouling people. Simplex Sam says he has never officially met the girl who lives across the alley from him, but he thinks she is a window dresser. She never pulls down the curtain. Did you hear about Prudish Prunella? She is in high school, and she refused to work a problem in fractions because the denominator was common. A straight line is the shortest distance between two pints, but after the first pint but few can walk it. While you are young is the time to make your fame and. fortune. About the only thing that goes strong after it gets old is cheese. A _ e