British Kinematography (1951)

February, 1951 63 TECHNICAL ABSTRACTS Most of the periodicals here abstracted may be seen in the Society's Library THE DUOMETER L. Busch and E. Herrmann, Foto-Kino-Technik , July, 1950, p. 219. A simple pendulum sensitometer is described for impressing two exposure patches on motion picture film. The two densities that result from processing are measured in a differential photometer to give a direct value for contrast, etc. G. I. P. L. COMBUSTION OF NITRO-CELLULOSE FILMS L. Amy, Bull, de V Assoc. Franc, des Ing. et Tech. du Cinema, 1950, No. 7. A survey of the chemistry of film combustion, and of its dangers, is followed by suggestions for prevention oi fires. The principal cause is stated to be neglect of safety regulations. R. H. C. EFFECTS OF INCORRECT COLOUR TEMPERATURES ON MOTION PICTURE PRODUCTION F. F. Crandell, K. Freund and L. Moen, /. Soc. Mot. Pic. & Tel. Eng., 55. No. 1, July, 1950, p. 67. The term "colour temperature " may be misleading when used to describe the colour balance of the illumination of a studio set. An instrument is described for determining the colour balance, and the factors controlling it and methods of expressing it numerically are discussed. THE STROBOSCOPE AS A LIGHT SOURCE FOR MOTION PICTURES R. S. Carlson and H. E. Edgerton, /. Soc. Mot. p,c. &, Tel. Eng., 55, No. 1, July, 1950, p. 88. Xenon filled flash tubes emit 24 flashes / second for iong periods at loadings up to 4 KW. When used for taking motion pictures they have the advantage 0f efficient production and utilisation of light and colour rendering similar to daylight. Their disadvantages are flicker, which is objectionable to actors, sharp images in each frame of rapidly moving objects, and noise. They may be useful for some special effects. F S H SIMPLE DEVICE FOR ULTRA-HIGH-SPEED PHOTOGRAPHY H. Bartels and B. Eiselt, Optik, Jan., 1950, p. 56, abstracted in Sci. et Ind. Phot., May, 1950, p. 193. The image is focused upon a small mirror rotating at high speed, and thence upon a series of stationary mirrors, from which it is focused upon stationary film. Exposures as short as 1/xs. at intervals of 'i MS. have been achieved. R H C INFRA-RED PHOTOGRAPHIC EVALUATOR S. Horsley, Amer. Cine., June, 1950, p. 196. In order to evaluate the rendering of materials under infra-red illumination used to simulate night shots, an image convertor tube is built into a portable unit, with viewing system and infra-red lamps. R H C STUDY OF SEALED BEAM LAMPS FOR MOTION PICTURE SET LIGHTING W. Blackburn, j/Soc. Mot. Pic. &> Tel. Eng., 55, No. 1, July, 1950, p. 101. Sealed beam lamps, which are tungsten filament lamps of the photoflood type with part of the lamp arranged to act as a reflector, are light-weight and efficient sources of light. They cast shadows which are not as sharp as those given by the regular equipment, and are not so amenable to masking by barndoors, etc., but it is shown that they can be used successfully both on location and stage sets with good photographic quality and a saving in production time. F S H PROCESSES FOR MECHANICAL COLOURING OF FILMS J. Marette, Bull, de I' Assoc. Franc, des Ing. et Tech. du Cinema, 1950, No. 7. A description of the Pathecolor process, in which films were coloured through stencils, the latter being produced by means of a pantograph system. R. H. C. " AQUAFLEX " SUBMARINE CAMERA Bull, de I' Assoc. Franc, des Ing. et Tech. du Cinema, 1950, No. 7. The " Aquaflex " submarine camera comprises a Cameflex camera built into a housing with horizontal and vertical stabilising fins. Lenses can be changed and focus adjusted from external knobs ; instrument dials are illuminated. Drive is from a 6volt accumulator. The housing is kept watertight by means of compressed air. R. H. C. " TRIARC " ARC LAMP G. Lechesne, Tech. Cine., June, 1950, p. 149. A projection arc operated on three-phase supply is provided with three co-planar carbons. At a current of 40 amps, the voltage drop between carbons is only 16 v. R. H. C.