Motion-Picture and Television Engineering
Motion-Picture and Television Engineering
methods for the recording and transmission of images using a combination of motion-picture and television engineering facilities. It brings together motion-picture engineering, television, and video recording and is the basis not only for the production of television films but also for an increasing number of the most recent cinematographic processes.
Five main trends have become established in motion-picture and television engineering: the direct motion-picture photographing of television films, motion-picture filming with video monitoring and recording, video recording of television images from the screen of a picture tube or directly from its electron beam, television video monitoring during the editing and printing of motion-picture films, and the transmission over a television channel of films photographed or printed on motion-picture film (television motion-picture projection). A sixth trend—the showing of special narrow-frame prints on the screens of ordinary television receivers by means of a special type of video recorder-player—appeared in 1969–70 as a result of the development of video recording methods using an electron beam. In addition, methods are being developed for combined motion-picture and television photography, the rerecording of magnetic video tapes onto motion-picture film, and the preparation of duplicate negatives of motion-picture films by rerecording the images using an electron beam.
The direct motion-picture filming of television films is the most common production method. In countries having advanced television the output of television films made by this method is several times the volume of ordinary motion-picture production. The inferior detail and contrast of the image in television viewing have determined the photographic technology for television films, which differs greatly from that of motion-picture production. The principal features are the extensive use of 16-mm motion-picture film and the greater productivity (since the scenes filmed are longer than in motion pictures), with predominant use of closeups. When photographing feature television films production costs are substantially lower because of repeated use of sets, the greater simplicity of set design as compared with motion pictures, and the longer duration of the scenes used in editing. The greatest increase in output is produced by easing the working conditions of the actors, since television films are photographed according to the plot sequence, and two or three television cameras are used simultaneously, just as in live television transmissions.
Motion-picture photography with video monitoring is aimed at further improvement of filming conditions and an increase in productivity. A number of sets of combined motion-picture and television equipment of various designs are used for this purpose. A set consists of one, two, or more motion-picture cameras, each of which has a small television camera attached to it. The image in the motion-picture camera and the television camera is formed by a common objective. The television image is transmitted continuously to the program director’s console, but the motion-picture image is filmed only at the director’s command. Multicamera photographing of television films has become very common, but one-camera and two-camera versions of such units are beginning to be used in the production of motion pictures. In multicamera television filming, the monitor images are transmitted to a console and are reproduced separately for each camera on video monitors. The scene being photographed is thus constantly visible on the console in three different aspects or perspectives. The cameras are controlled during filming by the director from the console. The television images from the camera that is operating at any given moment is also reproduced on an output monitor and can be recorded on a monitor video tape recorder. As a result, long episodes can be played and filmed without interruption between camera shots, since the filming is not only being monitored on the console but also can be repeatedly checked and discussed by means of the monitor video recording. The use of video monitoring thus appreciably increases the productivity of motion-picture filming.
The direct filming of television images from an electron beam without converting them into light also makes possible very high productivity because the electronic filming is usually done with several television cameras, using constant video monitoring. In the equipment developed for this purpose during the late 1960’s, motion-picture film moves within the evacuated chamber of a cathode-ray tube, replacing the usual screen, so that the electron beam forms a latent photographic image on it that is then developed and copied by ordinary methods. The detail of black-and-white films recorded in this way is several hundred lines per millimeter. Therefore, in many cases this method may compete successfully with other video recording methods and even with the direct photography of television using motion-picture techniques. The recorded image is also very sharp, which makes possible the production of high-quality duplicate negatives of television and ordinary motion-picture films, the rerecording of color-separation images on motion-picture film from magnetic video recordings, and the recording of alphanumeric data output from electronic computers.
Video monitoring during the editing and printing of motion-picture films was first used in the early 1960’s and has become common not only for the production of television films but also in motion-picture photography. The films being edited or printed are reproduced on a closed-circuit television screen, with any necessary corrections, as many times as necessary to solve a given technical problem. During the editing it thus is possible to choose the composition without cutting or splicing the film until the best solution has been found. In this case each version of the cutting is recorded in turn on an auxiliary track of the magnetic tape and is reproduced in continuous form on the output monitor of the video-sound editing console. In the printing of motion-picture films the video monitoring makes possible the choice of optimum color and shading for each piece of film (“start”) used in editing, without the necessity of printing and developing the monitored samples. The electronic color analyzer designed for this purpose consists of a cathode-ray tube with a scanning beam that strikes a color negative after passing through an objective and a system of dichroic mirrors together with photoelectric multipliers that create three color-separated video signals: red, green, and blue. The signals are amplified by video amplifiers and can be corrected by means of controls and converter matrices to conform with accepted conditions for the processing and printing of the film. As a result, a color image is formed on the output monitor that corresponds exactly (depending on the adjustment) to the positive color image produced on a motion-picture film under given conditons or to its image on the screen of a standard television set.
The television motion-picture projection of films began with television broadcasting and is the oldest operating procedure in the motion-picture and television engineering field. Over the 30 years of its development, its methods and facilities have changed repeatedly. Only the division of each projection unit into its three basic parts—projection, transmission, and optical switching (for uninterrupted switching from one projector to another and from the operating television camera to the reserve camera)—has remained constant. In the USSR and many other countries that are developing color television, the most common television motion-picture equipment for black-and-white and color projection are television cameras using vidicon or Plumbicon transmitting tubes. The projection part of such equipment usually consists of two or three motion-picture projectors for 35-mm film and one or two projectors for 16-mm film that use as light sources xenon lamps, powerful incandescent lamps, and sometimes arc lamps. The motion-picture projectors are arranged around an optical switcher in such a manner that an image may be fed from any motion-picture projector to any television camera in the unit by rotating the mirror and prism of the switcher. The film is projected at the frame frequency that is standard for television in the given country (in the USSR, 25 frames/sec), and at most television centers it is controlled from a central console. In some countries, such as Great Britain, France, and the Federal Republic of Germany, the more complicated television motion-picture equipment, operating on the flying-spot principle, is still being used. In this type of equipment light source is a cathode-ray tube and the transmitting portion consists of photoelectric multipliers; the film is moved continuously (with optical and electronic alignment) or intermittently but with a very fast pulldown (1.3 milliseconds per frame) by means of special pneumatic equipment.
REFERENCESBurgov, V. A. Osnovy kinotelevizionnoi tekhniki. Moscow, 1964.
Burgov, V. A. “Razvitie kinotelevizionnoi tekhniki ν SSSR.” Tekhnika kino i televideniia, 1967, no. 9. (Bibliography.)
Tolmachev, V. B. Tekhnologiia s”emki televizionnykh fil’mov. Moscow, 1965. (Bibliography.)
Tolmachev, V. B. Proizvodstvo telefil’mov. Moscow, 1971.
Ross, R. J. Television-film Engineering. New York, 1966.
V. B. TOLMACHEV