Journal of the Society of Motion Picture and Television Engineers (1950-1954)

beam then returns to its original position on the face of the cathode-ray tube to begin another cycle. Servomechanisms are used to remove picture instability. Thyratron tubes triggered by television vertical synchronizing pulses provide the nonsynchronous power for the main drive motor. Dichroic mirrors divert the flying-spot light beam to the respective photomultiplier tubes for color reproduction. An important development in the field of intermittent projectors was the 16mm fast pulldown projector developed by RCA for use in color television.103 By means of a three-pointed star Geneva coupled in series with a shuttle-and-claw type intermittent through a 3-to-l gear train, it was possible to achieve film pulldown during television blanking time, a period about 1250 jusec in duration. This extremely fast pulldown permitted the use of a flying-spot scanning system utilizing a color diplexer. 16mm Projector for Television Three new 16mm projectors for fullstorage operation were described in the Journal. The General Electric projector uses a gas-discharge tube104 while the new RCA105 and Eastman Kodak106 projectors use a tungsten source. 16mm Television Film Equipment The Ernst Leitz Co. in Wetzlar, Germany, further improved their 16mm professional projector, Model Leitz G-l, for television use. A Geneva movement with steadiness better than 0.1% is reported. A synchronized motor with special optics and still-projection equipment permit the projector to cover a variety of pickup tubes and to be used for straight projection. A 2|-hr continuous running time with 4500-ft magazines is reported with top film reel running vertically. Askania107 of Berlin has brought out a 16mm television projector of the nonintermittent type with optical compensa tion by means of a rotating prism (Figs. 14, 15). Television Rear Projection Television studio rear projection reached a new peak with the NBC production of Richard II when a screen 1 5 ft high and 60 ft long was used. This was illuminated by two 90-amp arc slide projectors using 4 X 5 in. slides made on a new heat-resistant glass. NBC has put a new type of screen into use made of blue latex rubber which has better diffusing quality than any before in use. It is said that one can stand at a 45° angle to this screen and see no noticeable difference in illumination from that observed at the perpendicular. This means less fall-off of illumination around the sides of the screen and a greater flexibility in the use of angle shots from widely spaced camera positions. Television Studio Techniques Television manufacturers came out last year with several very small television cameras — so small as to be almost in the size and weight class of 16mm movie cameras. Although this equipment was intended for industrial use, many broadcasters were immediately interested because of the exceedingly low cost. By year's end, over fifty broadcasting stations were using these cameras built around RCA's vidicon tube. RCA put a 4-lb vidicon camera on the market which retails for under a thousand dollars. More useful for the broadcaster was the Dage camera (manufactured by Dage in Indianapolis, and also sold by Du Mont as the "teleye"). This camera, the size of a brief case, is a complete camera chain in itself, into which have been incorporated camera and viewfinder, camera control unit, power supply and synchronizing pulse generator. It puts out an rf signal which can be tuned to one of several standard television channels and fed directly to the antenna terminals 358 May 1954 Journal of the MSPTE Vol. 62