American cinematographer. (1951)

FIG. 1 — The Acme Process Camera includes a color wheel for 3-color successive-frame photog¬ raphy. Film movement accommodates one, two, or three strips of film and maintains perfect registration on all three. The Acme Process Camera Designed especially to meet precision requirements of special effects photography, it is now available for 16mm as well as 35mm process work. By JOHN P. KIEL Producers Service Co., Burbank, Calif. The greatly advanced art of proc¬ ess cinematography today demands a special camera having a mechanism more highly refined than that found in cam¬ eras used in ordinary motion picture photography. LTntil recently, it was the practice to alter a standard motion pic¬ ture camera, such as Bell & Howell, Mitchell, Wall, etc., to meet the de¬ mands of special effects photography. This was usually done by the studios’ own engineering departments. While such cameras proved adequate for a particular procedure, the process depart¬ ments were often hampered by the limi¬ tations of the equipment. With the Acme camera, which is now available for i6mm as well as 35mm film, Producers Service Company has met the studios’ need for a specialized, yet versatile, process camera to increase the range of activity of the process departments. Color separation negatives, matte shots and other exacting process proce¬ dures require the highest degree of ac¬ curate and positive film registration. The film movement of the Acme Process Camera, therefore, is of the solid, or stationary, register-pin type. 'I'his par¬ ticular method of film registration is extremely accurate because the pins are mounted directly to the movement base and operation of the camera does not entail any motion or mechanical action of the register pins. In order to compensate for the in¬ herent shrinkage of film without sacri¬ ficing accuracy of registration, the regis¬ tration pins are in horizontal alignment. One register pin is “full-fitting” in the film perforation ; the other is “full¬ fitting” vertically and slightly undersize horizontally. The movements are so ac¬ curate that a single strip of film may be exposed in the camera a number of times and still maintain perfect regis¬ tration on each exposure. This ability of the film movement to duplicate registra BtO RECORD FIG. 2 — Typical three-color, three-strip reg istration locations. tion is assured regardless of the direc¬ tion of film travel. In the engineering process every pre¬ caution has been taken to eliminate the possibility of film damage ; the most important, perhaps, being the elimina¬ tion of pressure on the film during the pull-down cycle. After the film is located on the register pins, just before the shutter opens, a small amount of pres¬ sure is applied; but the accuracy of registration is not dependent on this pressure — it serves only to hold the film precisely in the focal plane during the exposure interval. Pressure and stripper plates of hardchrome plated stainless steel engage and disengage the film perforations on the register pins prior to and following the exposure. Perhaps one of the most distinguishOctober, 1951 • ing features of the camera’s film move¬ ment is its ability to accommodate up to three strips of film at one time, maintaining perfect registration on all three. Need for manual adjustments, when more than one film is threaded in the camera, is eliminated by the spring-loaded pressure plate, which auto¬ matically compensates for the varying film thicknesses, applying equal pressure to all. To enable the use of this camera in conjunction with existing studio equip¬ ment and procedures, the film move¬ ments are supplied with the register pins either above or below the aperture and with the large, or “full-fitting,” pin located at any one of the corners of the aperture. Moreover, the film move-ments are easily removed and completely ( Continued on Page 4.20) American Cinematographer • 401