International projectionist (Jan 1963-June 1965)

the smallest mistakes in the projection room erupt upon the screen in view of hundreds of patrons. In order to eliminate these occurrences, the projectionist ought to check and re-check his work. Certain key points such as the proper lens and aperture plate, proper reel, proper threading, proper carbon trim, and others require constant supervision because without a program of double checking the show may suffer. Another item that demands inspection and checking is the operation of the equipment. This is the section of the program that makes it necessary for the projectionists to have the specialized knowledge discussed in the first three sections, for without it the projectionist may find it difficult to adopt an effective preventive maintenance program for his machinery. Film Inspection Must Take Place First The last major topic considered in this section pertains to film inspection. A few brief remarks on this subject will suffice. First, if a projectionist wants a perfect show at all times, he must inspect all film before its showing. However, in many cases conditions may prevent the proper inspection. If this is the case, one must do the best possible job under the handicap. The time allowed for such inspection remains a controversial subject and until the question can be effectively solved the present unfortunate conditions must be tolerated. Again the factor of experience plays an important role in deciding the individual case. But the projectionist should keep in mind that his primary job is to run the film and maintain his equipment, and the film should arrive at the theatre in good condition; therefore, if film inspection interferes with the primary obligation of the person running the show, the inspection of film ought to remain secondary on the agenda of duties. Summary and Conclusions Most of the material presented here is a part of every good projectionist's background but it is advantageous to review basic concepts and goals periodically so that primary objectives gain predominance in setting goals. This report says that in order to adequately perform the duties required of him, the theatre projectionist should possess a background in (1) electronics, (2) mechanics, and (3) optics. It is with this background, plus the specialized skills necessary, that this magician of the theatre can present a flawless show. Sometimes overlooked, but equally important as his knowledge, is his International Projectionist attitude toward his profession. The projectionist is an artist who uses machines to paint pictures, and he can gain satisfaction from a "canvas" well done. The projection equipment resembles the surgical instruments in the operating room of a hospital, for unless the person performing the operation uses highly skilled techniques, the job is a failure. Therefore, when the projectionist fails to present a flawless canvas of picture and sound, his patient dies. The patrons of the theatre go home to watch television. iP PROJECTOR CARBONS Better Light! Lower Costs! RINGSDORFF CARBON CORP, East MrKensport. Pa. How electrical noise is produced . . . calculated • . . measured , . . controlled Here are the basic facts about electrical noise — how it originates in circuits . . . what terms describe it . . . how to measure it . . . how to design circuits to minimize its undesirable effects. The physical nature of the various sources of noise are clearly described, including such sources as thermal agitation or resistance noise . . . shot noise in vacuum tubes and semiconductor junctions . . . noise from spontaneous emission of electromagnetic radiation . . . and noise in gas discharges. This practical book also explains auxiliary mathematical techniques, and discusses the relation of signal and noise in various types of communication systems. For ease in use, the simple tuned circuit associated with a device for measuring average power is made the basic tool for analyzing ELECTRICAL 270 pages, 6x9 105 illustrations $10.00 By WILLIAM R. BENNETT Data Communications Consultant, Bell Telephone Laboratories, Inc. Each chapter in this helpful book begins in a simple, practical manner and works toward more complicated examples. For example, properties of thermal noise and its relation to blackbody radiation are deduced from basic laws of thermodynamics and statistical mechanics. You also will find a clear treatment of elementary quantum mechanics in discussions of the maser and of noise in semiconductors. And, in describing noise properties of various devices, the book fills in your working background with basic facts on junction diodes — transistors — gas discharge tubes— klystrons— traveling wave amplifiers— and others. Both independent and dependent noise sources are analyzed. In addition to the standard theory of noise figure and its significance, a treatment is given of the more comprehensive Haus-Adler theory of noise measure. Throughout, the book stresses the universality of noise-like phenomena. Noise formulas for diodes and transistors; noise generation to meet specifications; design of amplifiers for minimum noise effects— these and many other topics 'are covered. A comprehensive review of noise in the various methods of signal transmission such as amplitude modulation . . . frequency modulation . . . and the different lands of pulse modulation is included. January 1963 CONTENTS 1. General Properties of Noise 2. Thermal Noise 3. Distribution of Magnitudes in Noise Sources 4. Noise in Vacuum Tubes 5. Noise in Semiconductors 6. Noise in Electromagnetic Radiation 7. Noise-generating Equipment 8. Noise Measurements and Techniques 9. Design of Low-noise Equipment 10. Application of Fourier Analysis to Noise Problems 11. Noise in Communication Systems ' 1 INTERNATIONAL PROJECTIONIST Post Office Box 6174 Minneapolis 24, Minnesota Please send me a copy of "Electrical Noise" by William R. Bennett. (I enclose $10.00.) Name Address City & State 17