British Kinematography (1950)

Jan., 1950 standardisation and the kinema 21 Mechanical Standardisation These original specifications showed the same type of perforation for both negative and positive stock — a circle with two flats. At a later date Bell & Howell introduced the rectangular perforation which is to-day used on all positive films (with the exception of Technicolor and laboratory positives). Experience has proved the original contention that due to its radiused corners and slightly greater length, it gave a longer working life to the film. The American standards formed the basis of practice in every country in the world. Thus Newman's original endeavours have been crowned by the fact that to-day film mutilation due to mechanical mismatch is a thing of the past. There is, however, one matter not finally determined. For many years the intermittent sprocket has been made to a working diameter of about }f in. — actually from .932 in. to .936 in. Experiments in America have shown that a diameter of .943 in. gives rise to less wear upon the film, and this is the diameter which will be ultimately standardised. The principal reason for this increase in diameter is of course that modern film stock shrinks less than that of even ten years ago ; the indications are that the new tri-acetate base, unlike former safety base, has an even lower rate of shrinkage, and it may prove that a still larger sprocket may be advantageous. Film Mutilation Committee Nevertheless we may fairly say that on the whole, purely mechanical causes of film damage have been overcome. In 1946 the British Kinematograph Society appointed a technical committee, which included representatives of other interested bodies, "To investigate the problem of film mutilation in all its aspects, and to recommend appropriate action." Its report indicated that by far the worst causes of mutilation were various aspects of the handling of film. Most of the findings of this committee are embodied in British Standard Specification 1492 of 1948, " 35mm. Cinematograph Release Prints." The B.K.S. committee spent a considerable time studying the problems of mechanical damage of green prints. It strongly recommended that all prints when new should be waxed or otherwise processed, to prevent emulsion pick-up in the projector gate. This is a recommendation made in the above-named specification. Of even greater importance was the recommendation — which followed American practice — that the 2,000 ft. reel should be adopted for all release prints. This again is embodied in the specification, but as is generally realised, the requirement must necessarily come into operation gradually, because of the difficulty of replacing cans and transit cases. The 2,000 ft. Reel The advantages gained by the despatch by the renter of films in 2,000 ft. reels need not be stressed. Practically every projectionist insists — quite wisely — upon projecting double reels. To double up single reels entails removing alternately the leaders and run-outs of reels, and splicing the reels together ; at the end of the run, the film must be cut at the appropriate point (so losing at least two frames of film each run) and the leaders and run-outs replaced. Apart from the fact that the average standard of film splicing in the kinema is deplorably low, there is always the risk that the reels may be divided at the wrong place, and the leaders and run-outs joined to the wrong parts, either leading to confusion in subsequent runs. Another factor stressed in this specification is the need for visibility of change-over cues. When the cue dot occurs on a dark scene it is often difficult to see it unless it is clearly ringed in white. While this was a requirement of the original American specification it has been often ignored. The new specifica