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ABSTRACT
Television Recording
By W. D. KEMP
Various means of recording vision-frequency signals are considered. For high-definition television, photographic recording appears to be the only practicable method. The film may be moved at constant velocity or intermittently, and some known systems are classified under these headings and described with their advantages and disadvantages, particular attention being given to the two methods now in use by the B.B.C. Various factors affecting the performance of television-recording cameras are then discussed, such as picture joins, interlacing, loss of definition on movement, optical efficiency, film stability, emulsion pile-up, and spot-position modulation. A suitable arrangement of the vision-frequency equipment is dealt with, and the necessary electrical corrections are described. The factors governing the choice of a cathode-ray tube for recording purposes are discussed, while some possible improvements are indicated. The various transfer characteristics concerned have been measured. Contrast correction is discussed, together with possible ways of improving the overall performance, such as high-gamma recording. The conditions for making satisfactory positive prints direct from negative television pictures are stated. Some conclusions based on operating experience of continuous and intermittent systems are then given.
(1) INTRODUCTION
Still photographs of high-definition In Britain, initial development was
pictures are readily made, but photo concentrated on 35mm equipment, but a graphing such pictures on motion pic 16mm system has now been developed.
ture film in a form suitable for retrans The B'B-C consid*r the devel°Pmen< °f ,.fr , high-quality recording systems on both
mission presents some difficulty. A num / 0 c . , f
16mm and 35mm equipment to be of
her of methods have, however, been prime importance owing to the possisuggested and some of these are being bility of interchange of programmes with used successfully. other countries.
Abstract by Pierre Mertz of a paper first N. 5, England. This abstract is published
presented on November 26, 1951, and in through the cooperation of The Institution
revised form on March 11, 1952, at the of Electrical Engineers, Savoy Place,
Convention on the British Contribution to London W.C. 2.
Television, April 28 May 3, 1952, by This abstract is comprised of about 75%
W. D. Kemp, High-Definition Films of the original paper. All illustrations
Limited, 98 Highbury New Park, London except Fig. 8 have been retained.
April 1953 Journal of the SMPTE Vol. 60 367