British Kinematography (1949)

47 the final magnetic sound track will then need to be transferred to a negative photographic sound track, from which the theatre release prints will be made. The use of magnetic sound up to that stage will have the great advantage, that the distortion and errors inevitably incurred in the previous developing and printing of numerous photographic tracks will be eliminated. It is difficult, however, to visualise that the thousands of kinemas will be willing to go over to magnetic sound film reproduction, owing to the change necessary, and it is equally difficult to contemplate the film renters being willing to issue two different sets of film copies, one with magnetic sound and one with photographic sound. The question whether magnetic sound will ever ultimately come into the public kinemas is therefore quite a speculation because of the commercial difficulties mentioned above, as well as the technical difficulties it presents. On the technical side, the added magnetic coating, although only very thin in itself, will also occupy quite a considerable space on a 2,000 feet reel of film, so that either less film would have to be put on each reel, leading to an increased number of change-overs, or the spool boxes on all the thousands of existing projectors would have to be increased in size. A further technical difficulty for public kinema use would be the necessary reconstruction of the projector film gates to allow the highly abrasive magnetic coating to pass through smoothly. Even so, frequent renewal of the pressure pads would probably be necessary. In conclusion therefore, and so far as the future is concerned, I see a combination of both magnetic sound film and photographic sound film, both used to their best advantage — the magnetic sound film in the studios, because of the greater facilities it provides, and the photographic sound film in the kinemas because of the technical and commercial difficulties of replacing it there. Both systems will combine very happily in the future. I would like to end by expressing my thanks for the assistance and cooperation I have had from Dr. von Braunmuhl and from Col. Elliott, for preparing the slides for this lecture, and I am indebted to Mr. E. Penkala for the use of his micro-photographic equipment and for preparing the photomicrographs . II. MAGNETIC RECORDING IN FILM PRODUCTION Norman Leevers, B.Sc, A.C.G.I., F.B.K.S.* IT is the purpose of this symposium to discuss the magnetic system of sound recording in relation to the known conditions of film production, and to deduce, where possible, what modifications are necessary to the new system on the one hand and to present recording practice on the other to achieve fullest efficiency. Our starting point is therefore the way in which a sound department usually operates at present. Modern film production calls for sound recording units of various types, which may be classified according to their functions, as follows :— 1. Fixed installations for final mixing. 2. Studio equipment for original recording. 3. Accessories for recording wild tracks, guide tracks, or playbacks. 4. Newsreel recorders. The relationship between the various units which comprise a complete sound department is indicated in the diagram, and we note the important position occupied by the cutting room by virtue of which it is entitled to special consideration in any discussion on new methods of recording. Existing Technique Most sound departments will have as a nucleus a more or less elaborate ♦Leevers, Rich & Co., Ltd.