The motion picture projectionist (Nov 1931-Jan 1933)

22 Motion Picture Projectionist December, 1931 trical signals light takes on the same form as sound departed from the microphone. In fact, were one to tune in on a television broadcast with headphones he would hear a series of connected but seemingly meaningless sounds which would resemble nothing so much as a wide range of buzzing noises emanating from a sawmill. Special Receiver Used A special receiver, however, intercepts the television signals which are wider and carried along a lower wave length than regular radio signals. A highly sensitive light source recon• verts the signals into graduations of light. This light makes possible the remarkably brilliant pictures which Mr. Sanabria has been able to demonstrate. It is a small point-source lamp, not much larger than a type 250 radio tube. It is air-cooled and produces a whitish picture which is a distinct improvement over the red images of the ordinarily used neon lamp. It is capable of one hundred per. cent modulation, responding to as many as 100,000 light variations per second. In the recent demonstrations of Sanabria television this lamp has withstood the rigors of regularly scheduled demonstrations. Not once in fifty-six demonstrations at the Broadway Theatre was it necessary to halt a performance because of mechanical difficulties. Light Projected on Screen The light from, this glow lamp is projected on to the screen by means of a disc, similar in design and in the arrangement of the perforations along the circumference to the scanning disc at the transmitting end. In each perforation there is a lens three inches in diameter which magnifies each spot of light and projects it on to the screen. The motor operating the disc at the receiving end is synchronized with the power source at the transmitter. In no instance does the eye perceive a complete picture. There are a series of these spots of light which follow one another at so swift a pace that there is an optical illusion of a complete image. What is actually seen at any one time is one spot of light to which the eye clings until that spot merges with the next spot and so on until all of the constituent parts of the picture have flashed upon the screen at which time another picture is started. In every second fifteen distinct pictures flash upon the screen and each one of these pictures has approximately 2,500 elements. There are several reasons why Mr. Sanabria's images have been so widely acclaimed as superior developments in television engineering. The amplifier has the capacity of amplifying each impulse 2,000,000 times. It is the heart of the television system and is responsible for the startling amount of definition which Mr. Sanabria achieves. It is possible even to retouch the television images just as an artist would retouch a photograph. This retouching, of course, is done electrically and occurs instantaneously while the broadcasting is taking place. Universal Acceptance Inevitable The acceptance of television as universally as sound broadcasting now is accepted as inevitable. For the Fig. 3. View Showing Photocells time, however, there are many problems which must be solved. It is difficult to say at this time whether the scanning disc system which Mr. Sanabria has used so efficiently in his theatre apparatus will prevail to the exclusion of the so-called electrical scanning or cathode ray systems or whether it will ultimately give way before this newer system. Mr. Sanabria himself, despite the applause given the recent performances of his apparatus, has retired to his laboratories to develop completely new forms of television. He has worked with success in cathode ray developments and has produced a new system which utilizes the best features of both cathode ray and mechanical scanning. "Which system will ultimately prevail," Mr. Sanabria says, "I cannot say. For the purposes of theatrical presentation I feel that the scanning disc system such as the one we are now using is highly satisfactory, but great progress has been made in cathode ray experimentation and, as time goes on, that system might become the system for the home." As in every infant industry there is still a whole world of development work yet to be done. Through the presentation of Sanabria television units in theatres throughout the country, it is hoped that the public will be made "Television-conscious." Only a fraction of the population of this country : has encountered television in any form and, before television can make great progress, it must be supported by a public interest. There are problems of presentation and it is here that the television experimenter will ally himself with the talking picture man. There is yet to be developed a suitable technique for the development of talking pictures for television which will serve the same purpose as electrical transcriptions in sound broadcasting. For a long time to come television broadcasting will be confined to local origins, network broadcasting being at all possible after much more experimentation. Therefore, some such medium as the motion picture film must be used. Film is eminently successful as a television subject. The eye of the camera is much more exhaustive and encompassing than that of the television apparatus and much better pictorial results are achieved because of the advanced technique of motion picture production. One film can be syndicated to a hundred television broadcasting stations and the cost of casts of actors, settings for plays and the necessity of overcoming the problems of presentation are eliminated. New Sound Film Transmitter Mr. Sanabria has recently developed a talking film transmitter which was the cynosure of the many motion picture operators who attended the radio show at Madison Square Garden recently. In this transmitter a regular sound film can be transmitted over the air. Unlike some of the other film transmitters this one broadcasts talking pictures with the sound on the film rather than on a disc. A powerful Mazda light is used in the transmitters and the light originating in the lamp is broken up by a scanning disc similar to the one used in the regular scanning mechanism. The fragments or spots of light are then cast upon the film and a single photo-electric cell is used to pick up the light which filtered through the celluloid. The scanning disc used in the Madison Square film transmitter was of forty-five holes. It runs at fifteen frames a second in a proportion to the speed of the film, which obviates the necessity for a shutter inasmuch as the film moves continuously and not intermittently as in the regular screen projection. The sound being picked up off the film in the regular manner, the effect when received over the air is comparable only to that of the talking film when projected in the motion picture theatre. A Distinct Form of Entertainment As time goes on, television will become increasingly independent in its technique, withdrawing from both the theatre and the motion pictures in the evolution of a distinctive form of entertainment. Television will never efface talking pictures just as talking pictures never supplanted the theatre. It will, however, draw upon the resources of both stage and screen in its development. (Continued on page 36)