British Kinematography (1950)

September, 1950 • 91 TECHNICAL ABSTRACTS Most of the periodicals here abstracted may be seen in the Society's Library BLANK FILM W. Lantsch, Foto-Kino-Technik, January, 1950, p. 12. A plant for the manufacture of film base is described, having an output of a million square metres a year. The base is cast upon an endless belt, and after drying, sub-stratum is applied before the base is cut to length and wound. R. H. C. COLOUR MEASUREMENT OF MOTION PICTURE SCREEN ILLUMINATION R. E. Harrington and F. T. Bowditch, /. Soc. Mot. Pic. & Tel. Eng., January, 1950, p. 63. For a full comparison of the colour quality of motion picture projector light sources, the complete specification of the spectral distribution of the radiant energy is required. High intensity carbon arc sources, however, are shown to be a sufficiently close approximation to black body radiators in the visible part of the spectrum for the colour temperature to be a useful means of assessing colour quality. Measurements of chromaticity co-ordinates and spectral energy distributions are given to illustrate this point. A method of making direct colour measurements on the arc crater from various angles of view and of combining these measurements to give the colour of the light, is described. F. S. H. A NEW TECHNIQUE FOR THE PRODUCTION OF 16-mm. SOUND PRINTS Tech. Cine., January, 1950, p. 25. The Debrie Tipro sound reduction printer employs 32mm. stock, upon which two sound tracks are produced, each track a twin image of the 35mm. track, so avoiding the use of anamorphotic systems. (See Brit. Kine., 17, No. 1, July, 1950, p. 13.) R. H. C. NEW PROJECTION LAMP AND CARBON-FEED MECHANISM J. K. Elderkin, J. Soc. Mot. Pic. & Tel. Eng., January, 1950, p. 87. A feed system for a projection arc employs a separate A.C. motor for each carbon, each motor intermittently energised by means of an electronic impulse generator, and the rate of feed being thus independent of arc voltage. R. H. C. INDUSTRIAL SAPPHIRE IN MOTION PICTURE EQUIPMENT W. Bach and C. Wagner, J. Soc. Mot. Pic. & Tel. Eng., January, 1950, p. 95. Industrial sapphire is an artificially grown crystal, made in rods up to \ in., and in boules up to | in. diameter. This paper draws attention to possible uses, in particular for components subject to film wear. R. H. C. THE IMAGE ISOCON Paul K. Weimer. RCA Review, September, 1949, p. 366. Yet another picture pick-up tube for television is described in this article from the RCA Laboratories. This new tube is experimental, the object being to produce television pictures in which the signal-noise ratio is improved in the black portions of the picture. This is a desirable feature for American stations which use image orthicons exclusively as camera tubes, since these exhibit this defect under certain conditions. T. M. C. L. TELEVISION STUDIO LIGHTING A. H. Brolly, /. Soc. Mot. Pic. Eng., December, 1949, p. 611. LIGHTING DISTORTION IN TELEVISION Richard Blount, Ibid., p. 625. These papers should be read by all interested in lighting, particularly for television sets. The authors are practical men with many years experience of running a television station. The lighting set-up and filters are intended to give good colour response for image orthicon cameras and we, in England, must remember that there are differences with the various types of English camera tubes. T. M. C. L. PERCEPTION OF TELEVISION RANDOM NOISE Pierre Mertz, /. Soc. Mot. Pic. & Tel. Eng., January, 1950, p. 8. This is a mathematical article analysing the effects of " noise " as being analogous to grain in photography. The effect of noise on contrast of the television picture is also analysed, T, M, C L,