International projectionist (Jan-Dec 1939)

a non-exclusive license under Famsworth patents for television receivers, transmitters and "other radio and sound recording and reproducing apparatus." Famsworth has, in turn, acquired a standard non-exclusive license for broadcast and television receivers and electrical phonographs under RCA patents and also other non-exclusive licenses for television and broadcast transmitters and "for its other field of business." Neither organization acquires any right to grant sublicenses to third parties under the patents of the other corporation. APPROVE GOLDE REWIND GoldE Mfg. Co., originators of enclosed automatic rewinds, has received the approval of the Underwriters Laboratories on the re-examination of the Micro-Switch rewind of their manufacture. The Laboratories further recommends, in a recent bulletin, that the Enclosed Rewind be made a regular part of all projection room equipment. This recommendation is taken into favorable consideration by insurance under Forest, Expanding, Moves Effective Oct. 1, the new address of Forest, Inc., is 200 Mount Pleasant Ave., Newark, N. J. The change from Belleville, N. J. to these new and very much larger quarters reflects the rapidly expanding activities of this company, which recently added to its line of magnesium copper sulphide rectifier units a new Suprex projection lamp and a screen. All products will be marketed under the Forest name. writers and state code authorities in drafting their requirements. Among the advantages of the GoldE rewind are micro-switch operation that assures positive accurate starting and stopping— any film breakage stops the rewind automatically; automatic stopping when door is opened, and all parts carefully and expertly finished and assembled. Further details are available from either your local dealer or GoldE Mfg. Co., 1214 W. Madison St., Chicago. ALTEC RENEWS CIRCUITS Lincoln Theatres, Inc., and King Coal Theatres, Inc., of Marion, Va., has renewed Altec service contracts on six theatres, and contracted for service on two additional houses. M. & P. Theatres, of Boston, Mass., has renewed a contract to have Altec service the sound in 85 theatres throughout New England. GTE DECLARES DIVIDEND Directors of General Theaters Equipment Corp. have declared a cash dividend of 15 cents per share on the capital stock, payable Oct. 16 to stockholders of record Oct. 6. RADIANT LAMP CO. EXPANDS A plan to expand the corporate and financial structure of the Radiant Lamp Corp., Newark, N. J., has been approved by stockholders. The present sales executives will continue in direct charge. The Radiant plant manufactures a complete line of motion picture projection lamps. MOTION PICTURE FLICKER {Continued from page 20) samples that were considered as just perceptibly degraded. A discouraging thing about this flicker problem is that flicker has not existed •day after day and week after week. Flicker has been definitely an intermittent problem, and during times of serious trouble has demanded the attention of many men, who, however, to my knowledge have not yet arrived at a true and final answer. The intermittent nature of this problem is undoubtedly due to the many factors involved. With all the work that the sound engineers have done on flutter it seems odd that a situation should exist that requires the same quality of motion but very little has been done about it, and the studios think the manufacturers should seriously undertake the problem because it is rather costly to have to make retakes. Lamp Mechanism Vital Factor Mr. Joy: This is an interesting paper. As manufacturers we have always worked along the lines of producing a carbon -which will give a steady light. In fact, -we have been working along the very same lines which Mr. Grignon suggests. As evidence of this I refer to Fig. 6, which is taken from our paper on "Recent Improvements in Carbons for Motion Picture Studio Arc Lighting."* This illustrates that improvement in the carbons bas resulted in a very appreciable improvement in light steadiness. It should "be realized also that a good lamp mechanism is necessary for the steady burning of the carbon. In the Technical Bulletin "Recommendations on Process Projection Equipment" of the Academy Research Council, specifications and suggestions are given for burning a carbon in a proiection system under conditions which, if followed, will go a long way toward eliminating any objectionable flicker. This illustrates again that besides having a good carbon it is necessary also to burn it properly to obtain the steady light desirable for either background projection or other lighting appli ' To he published in a succeeding issue. cations connected with the motion picture industry. It is evident that the work of Mr. Grignon and also of the Academy indicates that we are all striving toward the same common end, that is, to make a perfect motion picture. Mr. Grignon stated in his paper that a flicker of around 6 to 8 cycles per second in frequency was most noticeable to the eye. Was this critical frequency established by observation or by some theoretical consideration? Mr. Grignon: With a large series of. tests we finally realized that those irregularities that were causing us the greatest amount of disturbance existed in the region of 6 and 8 cycles. This statement is not founded on any actual measurement, because to make such a measurement would require a series of studies and other technical data involving a great deal of work. However, it was quite apparent that this region presented the greatest disturbing frequencies. Mr. Laube: What is the reaction in regard to the way we drive the 20th Century cameras — by drive from the motor to the shutter? Mr. Grignon : It has been our experience that that would probably be better than the current type of drive. The best way to check this point is with a stroboscope which is accurately synchronized with the driving motor, preferably using a contractor on the motor to determine the flashing periods of the stroboscope. Early tests with a non-synchronized stroboscope were found to be misleading. Mr. Laube: We feel that we have very good motion in the shutters on the 20th Century cameras. Stroboscopic tests are quite perfect. In background projection shots it is very desirable that each frame of projected picture remain on the screen for a longer time than the total length of time the camera_ requires o record ft. When I refer to the length of time the projected picture remains on the screen, I am not including the element of time during which the shutter in the projector is uncovering or covering the aperture, but only the time when the picture has its full value on the screen and is not being dissolved in or out by the projector shutter. If this time period is long enough to overlap that of the camera's total re cording time period, I feel that the condition thus described would be most ideal for flicker elimination in background projection shots. Mr. Grignon: In background projection work that is important. If we assume a 7° variation in shutter operation, which we have observed, then, the projection shutter should be 14° wider than the camera shutter, or vice versa. In using a three-head or three-projector type for projection there is some improvement because the change in any one shutter affects only one-third of the total light and the result is only one-third as great also, there being three shutters, the change is more at random and the defect is not as serious. Mr. Kellogg: Would you consider a disturbance that might occur every four seconds as disturbing? Mr. Grignon: Offhand I would say that such a disturbance, unless of large magnitude or occurring simultaneously with other factors, would not be disturbing. Studio Practice on Takes Mr. Richardson: In the illumination of motion pictures, we do not have any rotary arc that carries the rotation of the positive carbon as high as 15 rpm. Practically all the modern lamps of the high-intensity rotary type operate at a positive rotation speed from 6 to 12 rpm. There is another potential cause of flicker in the taking of pictures. In some studios it has been a practice to stop the rotation of the positive carbons during picture takes. This has come at the insistence of the sound recording departments in an attempt to reduce the mechanical noises from the high-intensity spot equipment. Some time ago a Committee of the Academy made a study of arc noise reduction. For this test work we had available to the Committee one of the quietest stages in the industry, a stage on which the ventilation system was made inoperative and the ground-noise cut to a very low level. The test was made with a battery of ten 150-ampere h.-i. arc spots centered around a microphone of the type used for recording dialog, in a semi-circle having a 25-ft. radius. Studies were made to ascertain the effects resulting from bringing the arcs into good trim and then 1*4 INTERNATIONAL PROJECTIONIST