Kinematograph year book (1950)

484 The Kinetnatograph Year Book. the most suitable projection illuminant ( 1 6) . The discharge lamp has nevertheless proved itself suitable for substandard projection, showing an efficiency far superior to that of the filament lamp ; unfortunately its lack of red rays mars the reproduction of colour films. A new light source claimed to produce light the colour of sunlight is the Siemens gas-arc. In this case the discharge occurs at high current density through xenon. Although the efficiency is rather inferior to that of mercury, the improved colour may compensate for this Sound Equipment As I have long advocated, sound equipment today generally forms part of the projection equipment, rather than being supplied as a separate unrelated piece of apparatus. In the two projectors mentioned earlier, the B.T.H. SUPA and the Kamm, the sound head forms an integral part of the picture mechanism, while in the remaining machines the mute and sound heads are separate units, and different makes of sound equipment can if desired, be used. The need for a high quality of sound reproduction is today universally recognised, and modern equipment is seen in even the smallest kinemas. One outfit which is particularly suitable for the small show is the Kinetechnic, which in a small compass provides complete stand-by facilities (1S). It is, however, gradually being recognised that the limiting factor in reproduction quality is the acoustics of the kinema. It has been claimed that the science of acoustics has made important advances in the past ten years, and that future kinemas may be expected to show progress in this respect. The French equivalent of the B.K.S. has made a study of the subject, but it is to be doubted whether its findings will be generally accepted (19). A long-debated question is, to what extent can stereophony improve the quality of sound reproduction ? I had the privilege of hearing music over a stereophonic channel in the Philips electro-acoustic studio in Eindhoven, Holland, and was satisfied that the realism of reproduction was much enhanced ; it has been suggested that kinemas debarred from opening for films on Sundays might instal this equipment and run Sunday concerts for music lovers. But when we consider stereophonic reproduction of the sound accompanying films, it must be remembered that to a large extent stereophony is already assured by the fact that the speakers are positioned just above the centre of the screen, where generally the cameraman places the close-up heads of his characters. Magnetic recording, both on tape and on perforated film, is receiving close attention in the studio, and should be considered by the exhibitor who is anxious to provide interludes of a quality superior to that of discs. The system lends itself to the recording of announcements and advertising items, which can be reproduced as often as desired, and erased when finished with. Arc Rectifiers In the field of arc rectifiers, a number of questions remain unanswered : should the rectifier be placed in the projection room or in a separate rectifier room ? Should the projectionist be able to vary the current to his arc or should it be preset ? Is mercury or selenium the f^LEN^ENA j 1 THE SOAPLESS CLEANSER 3 Has all the qualities of soap1 and more. Clenagena is unrat.oned. A product of \ NEW HYGIENE LTD. makers of GERMSPRAY ♦ MfTOJNA PINAGENA ♦ /"^S J (Air-Conditioning Box) HYGIENE HOUSE 266-8 HOLLOWAY ROADLONDON -N 7 Telephone NORTH 5041-2-3