Journal of the Society of Motion Picture Engineers (1930-1949)

ABSTRACTS 115 1930, p. v. A new sound reproducing equipment, the Brown Magnetorge, is being marketed by Magnetic Talking Pictures, Ltd. Transmission is by means of a "magnetic torque motor," a principle said to be novel to cinema work. A special optical system is employed so that the light, after passing through the sound track, is reflected to a photo-electric cell placed centrally between the two projectors. Brown amplifiers and loud speakers are used. The complete equipment for sound-on-film and disk costs $2750. Selenium for Talkies. R. H. CRICKS. Kinemat. Weekly, 163, Sept. 11, 1930, p. 55. The Automatic Light Control Company, Ltd., has developed an improved form of selenium cell. A brief description is given of the method whereby selenium is deposited on a glass plate so as to give a very wide short current path of small internal resistance. Tests have shown that the cell is not susceptible to fatigue or temperature changes to any measurable extent, and that the time lag can be corrected by an amplifier with a suitable inductive circuit. The cell is not sensitive to color changes. R. C. A. Aids the Hard-of-Hearing Fan. Ex. Daily Rev., 28, Sept. 20, 1930, p. 18. Persons whose hearing is defective are supplied with direct telephone connection to the amplifier. A receiver is held to the ear by means of a lorgnette handle, and a cord extends to a plug for a receptacle on the arm of the seat. The volume of sound can be controlled to suit the user. New Continuous Printer. L. EVELEIGH. Kinemat. Weekly, 162, Aug. 21, 1930. p. 65. The Vinten continuous printer for sound films is described. Contact is established by a curved gate with a flattened aperture through which the films are pulled at the correct tension by a specially designed sprocket wheel connected by a spring coupling to a flywheel on the same spindle. Uneven running of the sprocket is thus damped by the inertia of the flywheel. A universal fitting allows for the insertion of any type of printing lamp for the picture, while a 12 volt lamp is used for the sound track, provided with an ammeter and a control. The speed of printing is stated to be 120 feet per minute, and arrangement is made whereby batteries of printers can be placed in line, the negative running directly from one printer to the next, thus making any number of prints with only one final take-up. A brief description is given of the novel automatic light change incorporated. This is controlled by a number of circular disks mounted on a spindle with friction clutches. Normally, the disks are held stationary, slipping on their axle while the spindle rotates. By means of electromagnetic releases operated by a chart, any one of the disks is released and rotates with the spindle to make contact and give a predetermined exposure. When the exposure is to be altered, the release of another disk moves the contact block which has been engaging the first disk, so that it completes its rotation into its original position. Some Experiments in Mobile Color. G. A. SHOOK. /. Opt. Soc. Amer., 20, June, 1930, p. 35. A convenient "organ" for producing lights varying in form and color is described. Unlike the Clavilux which utilizes a large number of specially constructed lamps, this new instrument has a single light source and three rotating disks on which are placed the various optical devices and colored filters for producing the mobile light forms. The instrument readily lends itself to automatic control. Devices for Silencing Cameras. Ex. Herald-World, 100, Sept. 13, 20, 1930,