The motion picture projectionist (Nov 1929-Oct 1930)

January, 1930 The Motion Picture Projectionist 39 Develop A Non-Intermittent Projector in England ANEW projector, claimed to have no intermittent movement, was recently demonstrated at the laboratory of its inventor at Kingston-onThames, near London, England. The projector is being marketed by PhotoVision, Ltd., and is called the Continuous Motion Projector. Among the three major problems, claimed to have been solved with this new projector is the fact that it enables the sound track to be placed on the margin of the frame to which it refers, instead of 19 frames away, it eliminates the possibility of buckling in projecting wide films and that it does away with strain on film making its projection life almost unlimited. No Mirrors or Prisms The projector was developed by Messrs. Roberts, Campbell and W. E. John and according to its inventors, it is now possible without the aid of mirrors or prisms to project a continuously moving film by a direct beam. The projector works with the aid of a series of lenses arranged in a channel formed like the letter "D." These lenses are kept equidistant by the construction of their mounts. The lenses are driven round in their groove, keeping pace with the film which runs parallel to the straight portion of the "D" shaped groove, and each frame in the film is opposite to one of the lenses. By the action of the mechanism, it is claimed, each lens keeps with its particular picture until it passes out of commission at one end of the straight channel, to return by the curved part of the "D" to the other. By adjusting the size of the gate, one, two or three frames may be projected simultaneously. The images of each of the lenses are Front view of New Contner sound film recorder received on a large master lens, which combines them into one single image. This master lens, which is stationary, fixes the optical center, and causes the two or three moving frames to be superimposed on the screen in one perfectly stationary and flickerless picture. The first optical advantage obvious at the demonstration of this system was a sense of visual ease, due partly to the fact that movement is seen as transitional from one position to another, instead of jumping from onepoint to the next, and partly to the entire absence of alternating periods of light and darkness, which is a fundamental disadvantage of the intermittent system. New Type Fader This new fader which the Operadio Mfg. Company has recently incorporated in their line is of the 12-contact point type. Unlike the usual potentiometer type, each contact represents a definite wire-wound resistance, in suring at all times a constant and positive increase or decrease of amplifier input voltage, and is not subject to deterioration with use or fluctuation in value, due to temperature or weather changes. Each side is arranged with steps scientifically graduated so that when a switch-over is made from left to right, there is no sudden "click" or rush of music so undesirable in a fader. This fader is adapted for high impedance lines, being particularly suited for fading between pickups of 2,000-3,000 ohms impedance. The fader itself is mounted in a steel box, provisions being made so that conduit wiring can be run right into the box, thus meeting the Board of Underwriters' specifications. The fader itself incorporates a change-over switch enabling it to work on either disc or sound-on-film equipment. Everything in the construction of the fader is of the very best. It is a real, positive-working fader. It is also equipped with a dummy fader, coupled with the fader through a set of gears, which is known as Model No. 341-D. The dummy, in outward appearance, is exactly the same as the fader itself with the exception that the switch is left off. Driving mechanism of New Contner recorder. Mr. Contner is associated with Blue Seal Products Corp. Double Screen Grid Tube Now Reported A new tube is reported to be in the finishing process in development laboratories. It is described as a double screen-grid tube, intended to be ready for the public next season. Only one additional wire would be necessary in the receiver and this would provide the bias for the second screen, the tap for which would come from the base of the tube. This bias may be 7% to 12 volts positive. The intended circuits used will be similar to those now in vogue (Continued on page 48)