British Kinematography (1950)

60 BRITISH KINEMATOGRAPHY Vol. 16, No. 2 DIRECT-POSITIVE VARIABLE-DENSITY RECORDING WITH THE LIGHT VALVE. C. R. Keith and V. Pagliarulo, /. Soc. Mot. Pic. Eng., June, 1949, p. 690. The application of supersonic A.C. bias to variable-density recording is described, and it is shown that in direct-positive recording the linearity of the toe characteristic is considerably improved, giving high output level, low distortion and good signal-to-noise ratio. N. L. LEAD SULPHIDE PHOTOCONDUCTIVE CELLS. S. Paksever, Electronics, May, 1949, p. 111. A general description of the method of forming a light-sensitive lead sulphide layer is followed by some useful performance data in respect of spectral response, frequency response, and noise level. Comparisions with two other types of cell are made. N. L. FROM THE OVERSEAS PRESS Publications quoted may be seen in the Society's Library. NEEDS OF THE BENGAL FILM INDUSTRY In a report submitted to the Ministry of Industries and Supply by the Bengal Motion Picture Association, it is mentioned that the industry employs 20,000 persons. In Calcutta and suburbs there are 14 studios having altogether 35 stages. Raw stock needs total 166,000,000 ft. per annum, practically all obtained from Kodak. It is stated that equipment has to be obtained from dollar sources. Journal of the Bengal Motion Picture Association, Nov., 1949. THE KINEMA IN NATURAL RELIEF The " Verivision " system of stereoscopy consists in the production of films carrying rightand left-hand images, which may be differentiated by known means, as b> polarised light. A feature of the system is that the stereoscopic distance in taking is varied according to the distance of the object, the stereoscopic angle being maintained at about 0.6°. Cine Amateur, Dec, 1949. BOOK REVIEWS Books reviewed may be seen in the Society's Library ELEMENTS OF SOUND RECORDING. followed by a detailed explanation of John G. Frayne and Halley Wolfe. " density " and " area " techniques, methods John Wiley & Sons, Inc. Chapman & of noise reduction, and the vital subject of Hall, Ltd. $8.50. film processing. The progress of the advanced student Sound reproduction is dealt with in specialising in sound recording has been chapters on re-recording, 35 mm. systems, sadly hampered by the lack of a suitable 16 mm. systems, loudspeakers, and acoustics, text book, and the publication of one which A section on magnetic recording describes so admirably fills the need is an event of basic principles and includes up-to-date note. This book is compiled from the U.S. information on apparatus and suitable Government wartime training courses given applications of the system, by the authors at the University of California, With many excellent photographs and suitably .expanded and brought up-to-date. diagrams, and the absence of serious errata. The early chapters, which deal with some there is evidence of painstaking care in of the fundamentals, such as wave motions, preparation. Numerical examples of cal acoustics, and mechanical systems, are culations are given wherever these assist the written in a style and terminology which not explanation and there are references to other only sets out very clearly the analagous sources of information at the end of each behaviour of mechanical and electrical chapter. Advanced student and professional systems, but also leads smoothly into the sound engineer alike will find so much consideration of specialised apparatus. detailed information of daily use in this Sound transmission components such as book, that it will certainly become a standard microphones, amplifiers, filters, etc., are work of reference on sound recording, then dealt with, valuable information on the Norman Leevers. design and methods of use being given, in each case, and passing chapter by chapter from the general to the more specialised THE PHOTOAMATEUR'S POCKET items such as compressors and limiters, and BOOK. Focal Press. 5s. thence to the consideration of methods of Although intended primarily for the recording. Separate chapters are devoted amateur this little pocket book-diary is to systems of photographic recording, disc packed with information for the professional recording, and disc processing, and are photographer and kinematographer. It is