Cinema Canada (Apr 1979)

TECd NEWS eliminated by the development recently of Rank Cintel’s Digiscan system of frame rate conversion. This development has made the flying spot scanner very attractive for North American service, and a considerable number of post production companies have already installed or are planning to acquire this new film reproducing equipment. With the Digiscan system, scanning takes place at the film frame rate — 24 frames/sec. — and the required number of television lines are generated to make up two complete television fields for each film frame. The odd and even television lines are “written” into different computer memories or stores. The odd lines are then read out of the memory for the first television field, while the even lines are read out to produce the interlaced field. As the Digiscan system stores the luminance and chrominance information (brightness and color) separately, two fields of storage are needed for each, or four altogether. The operation of the system is completely automatic. The system can also scan out still frames when the film transport is stopped. DREAMSPEAKER and TEM EYOS KI AND THE LAND CLAIMS QUESTION by CAM HUBERT (B.A. Cameron) Created by the powerful writer of the searing docu-drama Drying Up the Streets, the Etrog award-winning Dreamspeaker is now in print alongside a haunting novella which . is a brilliantly written piece in which Hubert unleashes a mocking, playful wit.” Toronto Star $10.95 Please send DREAMSPEAKER to: copies of Name Address ee) CLARKE IRWIN 791 St. Clair Ave. W., Toronto, Ontario M6C 1B8 32/Cinema Canada Multi-Format Telecine Operation The Rank Cintel Mk II flying spot scanner is designed in such a way that a change-over from 16mm to 35mm film can be effected by simply interchanging the unit containing the film gate and transport mechanism. This is a big advantage in a post-production operation where clients may bring in either or both film formats to be transferred to videotape. To accommodate the two film formats a camera type telecine chain would have to include a separate projector for each format to give the same degree of flexibility. The flying spot scanner was developed in a television environment where manual adjustment of the video controls was the normal method of operation, the objective being to obtain the best possible television pictures from film. This type of equipment is fitted with a more comprehensive range of controls as compared with cameratype telecines commonly found in North American television stations. For example, controls are available to alter the gammas of the three color output signals. With this type of control it is possible to completely change the appearance of the television pictures by raising or lowering the signal levels from the picture middletones relative to the highlights or shadows. Gamma correction is particularly helpful in reproducing films in which the images in all three layers have not been exposed in the same portion of their characteristic curves, or when these relationships have been disturbed by faulty processing of the color film. Post Production Operations with TOPSY Available also with the Rank Cintel Mk III flying spot scanner is a device known as “Topsy”. With this device corrections of the telecine controls made during previewing of a film can be stored in a memory (floppy disc), and recovered later on, automatically, scene-by-scene, during the transfer of the film to videotape. This enables preparation of the transfers to tape to be carried out in much the same way as color film negatives are prepared for printing in the motion picture laboratory. However, during a film preview in telecine, the change in picture appearance produced by a given shift in the setting of a telecine video control can be seen as the change is being made, by observing the television picture monitor display. If the desired improvement in picture appearance is not obtained with this particular setting of the telecine control, the film can be rewound and the scene can be run through again with a different control setting. Stopping, rewinding and restarting of the film transport can be accomplished much more easily and quickly and with far less risk of film damage, aS compared with an intermittent pull-down film projector. Advantages and Disadvantages From this brief and rather sketchy description it can be seen that the flying spot scanner is quite different than the more familiar camera-type telecine. The biggest difference is that film projectors are not used — instead, the film transport is an integral part of the /scanning system, and the film is moved continuously through the gate where the images aré scanned by a moving spot of light. A television camera is not used in the flying spot scanner — the light passing through the film images is collected in photomultiplier tubes to generate the video signals. These devices are basically similar to the photocells used in generating sound in a film projector, except that the output signals are amplified many times within the tubes, as the name suggests. It would be misleading to leave the impression that the flying spot scanner is inherently superior to the vidicon telecine insofar as the ability of these devices to generate high quality pictures from film. But anyone who has had the task of lining up a vidicon telecine would almost certainly agree that a great deal of time, effort, skill and determination is needed to achieve a condition of film reproduction acceptable to filmmakers. From what has been seen so far it appears that such a condition is easier to achieve in the flying spot scanner operating with the Digiscan system. Long time Supervisor of Technical Film Operations at the programming centre of the CBC, Mr. Ross is the author of two books, Television Film Engineering and Color Film for Color Television, has won the Agfa-Gevaert Gold Medal awarded by the Society of Motion Picture and Television Engineers, and is presently Chairman of the SMPTE Board of Editors.