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1945 Theatre Catalog, 4th Edition, Page 582 (554)

1945 Theatre Catalog, 4th Edition
1945 Theatre Catalog
1945 Theatre Catalog, 4th Edition, Page 582
Page 582

1945 Theatre Catalog, 4th Edition, Page 582

pictures for demonstration to larger audiences. There have been three main lines-of development, each of which has had a practical result: .Mechanical Systems, Intermediate Film Projection Sys tems, and Cathode-RaysTube-Projection '

Methods. To these .can be added a .fourthelight valve systems-which is in process of development but has not thus far yielded a satisfactory practical result. - i Mechanical SystemseMechanical systems were founded on the use of mirror drums or lens discs rotating at high speed to effectvthe reconstitution of the image. In general, it has been found impossible to operate such systems on a definition higher than 120 lines, and the

need for a very much higher definition

standard in the cinema has rendered obsolete-the use of such mechanical sys tems where, in addition, the light out- put is severely restricted. It is worth

while, however, to refer to two methods where reasonably good results have been

achieved. One is the Scophony optical mechanical system where the use of a (fstorageii light valve has enabled a much greater picture brightness to be achieved for what is fundamentally a mechanical system. This system has been developed to a stage where- largescreen pictures of good definition and brightness have been, as will be described later, , commercially exploited. The other is to a large screen color demonstration-given by J. .L. Baird in the Dominion Theatre, LondOn, in 1938, where a two-color system was used and pictures. were-reproduced- by rear projection on a-.screen 10x8 feet. This

- demonstration 'was introduced into the

regular theatre programrfor paying andiences fora period 'of some weeks. Intermediate Film ProjectioneThis

method consisted of photographing the

television picture reproduced on a small cathode-ray tube on. a film which, after rapid development, fixing, and drying, was projected asa standard film through

the usual 35-mm. projector. The ad FlGURE 4.-A rear View is seen here of the Baird Jorge-screen, double-headed proiector unit, installed in the New Victoria Cinema, in London, in April, 1939. Seen in the picture are the proiector tubes and the controls, and in the background can also be seen part of the 12xl5-ioot television screen. Again installed in the center of the auditorium, the equipment required the removal of a certain number of seats in the theotre's choicest location.

.3 7n;

vantage of this process, which was developed both in Britain and Germany, and demonstrated to theatre audiences in 1935, is that it is possible to provide the normal standard of brightness on the theatre screen because the processed film passes through a standard projector. The degree of definition was quite high, but the method proved to be somewhat expensive, due to the high film costs incurred; the 60-second delay in reproduction due to the time of processing of the film was not regarded as a serious defect. Such equipment in practice, however, needed a very high degree of supervision, and the maintenance of the processing baths and of the mechanical parts of the projector is regarded as being semewhat beyond the practical limitations imposed by the day-by-day continuous service of cinema projection. However, there are many who still have faith in this method of television presentation, because it has the additional advantage that, by putting the received television picture on film, a permanent record is made in the theatre and this could be used over and over again in subsequent performances. Cathode-Ray-Tube Projection. -- This method involves the stepping up of the normal cathode-ray-tube television receiver of the home to a high-power basis, so that intensely brilliantimages of a size approximating 6 inches in diameter can be projected by efficient lens or mirror systems to the full cinema screen size. At this present moment, this method appears to be the one offering the most scope for future practical development. It formed the basis of the equipment developed by the Baird company for installation in 1938 and 1939 in the theatres of the Gaumont-British Picture Corporation. The historical development of these installations follows. Early in 1938, a small projector was installed in the Tatler Newsreel Theatre in London (Figure 1). It consisted of a cathode-ray-tube, operating on 30,000 volts, and reproduced an intensely bright picture approximately 3 x 4 inches which was projected by a f/2.5 lens on to a screen 10 x8 feet (Figure 2). The illumination on the theatre screen was of the order of 1 foot candle and demonstrations were given of various actuality programs transmitted on the 405-line basis by the B. B. C. These were mainly in the form of private demonstrations and for a small theatre of that type, with a total seating accommodation for 683 people, the results were regarded as eminently satisfactory. The equipment was entirely of an experimental nature and could not be handled by anyone but a specialist. These results gave encouragement for further work in larger theatres, and, early in 1939, the Marble Arch Pavilion with a seating accommodation for 1,290 was equipped with a higher power, dual cathode-ray-tube projector, operating on 60,000 volts, providing an illumination of 1 foot candle on a screen 15x12 feet (Figures 3, 4, 5, and 6). This equipment was used for special programs on a commercial basis for paying audiences and the success of the results achieved led to the Gaumont-British Picture Corporation's ordering 12 equipments for installation in

1945 Theatre Catalog, 4th Edition, Page 582