Film and TV Technician (1957)

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FILM & TV TECHNICIAN January 1957 A Technician's Notebook MIRROR SCREEN FROM POLAND \ POLISH engineer, Jan Anto^* siewicz, has evolved what appears to be a novel solution to the problem of projecting films in a normally lit room. The conventional matt white screen scatters light in all directions through an angle of 180°, which, though it enables spectators to view the picture on the screen from even the most acute angles, is wasteful of light diffusing it in all directions beyond the range of the audience. To make the picture visible on such a screen either the auditorium must be darkened, or the screen recessed. In his search for a solution Antosiewicz turned to the ordinary mirror which reflects light at the angle at which it strikes the mirror and without diffusing it. The plane mirror is obviously unsuitable for using as a cinema screen so it was the convex mirror that Antosiewicz used as the basis of his screen — millions of minute convex mirrors, each mirror measuring 0.54mm. by 0.18mm., their rectangular shape ensuring the diffusion of light from them to the occupied space of the auditorium, but excluding the ceiling or the floor. It is claimed that the coefficient of brightness of the picture on the mirror screen is between twenty and thirty by comparison with the white screen. The article from which the material above was taken, and which was kindly placed at our disposal by the Polish Cultural Institute, goes on to say that to prevent the reflection of any other surrounding objects in the screen, Antosiewicz used a " counterscreen ", a black cloth spread before the screen at such an angle to the screen as to be visible from anywhere in the auditorium as a uniform black sheet. This probably means, though the article does not make it clear, that the screen would have to be first of all set at a height and angle which would ensure that the audience itself does not produce reflections in it. The tiny reflectors are mass produced in pressed aluminium, from a die which consists of several thousand " negatives " of reflectors, arranged at regular intervals. The aluminium plates, impressed with the convex reflectors, are then glued on to a large By A. E. JEAKINS sheet to make a screen of the required size. " From a practical standpoint the electronic recording of motion pictures is an accomplished fact " says Frederick Foster in an article in the American Cinematographer. He points out that no development relating to motion picture production has aroused greater interest than that which has to do with the electronic recording of the picture image. Though Bing Crosby Enterprises, followed by R.C.A., announced developments of such systems several years ago, no practical equipment has been put on the market by either company. In May Ampex, a manufacturer of magnetic recording equipment, demonstrated their Videotape recorder, a complete record and playback unit capable of recording and reproducing commercial monochrome TV material. The machine was designed specifically for the purpose of television programme delay, and Ampex have said that it will be first employed for this purpose only. Addressing the convention of the SMPTE in New York and referring to speculations about the use of Videotape equipment for producing motion pictures, R. H. Snyder of Ampex said, " Any speculation on the replacement of the 35mm. camera by Videotape is, in our belief, foolish at this time." He thought that a director might shoot simultaneously on film and tape, using the tape as an imme diate pictorial playback. Videotape picture quality was not comparable with ordinarily good original film and not even remotely comparable with the newer large negative processes. The Ampex system records both picture and sound on a single twoinch wide tape. Picture quality is .'aid to be considerably better than that obtained with current kinescope techniques. The recorder works on the same principles as are used in a standard sound tape recorder. But to obtain the 4-megacycle response needed for picture recording the tape speed would have to be 2,000 inches a second; at that speed a reel of tape 14 inches in diameter would run for only 29 seconds. Ampex have developed a system which works at a tape speed of 15 inches per second, by using a magnetic head assembly of 4 heads mounted on a drum which rotates at a high speed recording transversely across the tape instead of longitudinally. This gives an effective tape speed sufficient to record and reproduce the 4-megacycle band width. The sound is recorded normally along one edge of the magnetic tape. Thrillarama is the latest development of wide screen procedure. According to limited information available at this time the salient facts are : The photographic system, using two cameras side by side with an interlocking device, registers scenes on separate 35mm. negatives, using full aperture on both. Later the two films are synchronised for showing on a theatre screen at a ratio of approximately 31. to one. It is claimed that both close-ups and long shots are photographed without distortion in presentation. Sound track is on a separate reel. The cameras were made in France, but the photographic system was designed, engineered and built by Raphael G. Wolff Studios in Hollywood.