International projectionist (Jan-Dec 1956)

LETTERS TO THE EDITOR (Continued from page 19) that they contact only the perforation margins of the film. When the plain, drum-type roller is used, the projectionist must keep the film-contacting surface scrupulously clean and free from burrs or scratches in the metal which might conceivably damage the film. Pressure Against Film Even though film tension in penthouse reproducers may seem rather low (3 to 5 ounces), it should be remembered that all of the "drag" on the film is exerted by direct contact with the ETHYLOID FILM CEMENT IS RAPIDLY BECOMING THE ACCEPTED STANDARD IN THE MOTION PICTURE INDUSTRY-FROM STUDIO LABORATORIES TO THE PROJECTION ROOM. AVAILABLE AT ALL THEATRE SUPPLY DEALERS FISHER MANUFACTURING CO. 1185 Ml. Read Blvd Rochester 6, N. Y. curved surfaces of the pickup shoes. The pressure of the film against the pickup surfaces is therefore high — much higher than at any other point in the entire projector film path (exempting from consideration certain obsolete optical soundheads employing clock-spring pressure pads at the sound gate). This fact is an important factor in film multiation only insofar as the film rubs against places on the pickup head other than the track-contacting shoes. Excessive pressure may bend the film inward to rub against the very slightly depressed middle part of the pickup device. Result: "rain." Optical-track prints, it is also well to remember, have sometimes been damaged as a result of penthouse soundheads being installed on a projector; but these prints, usually threaded up to bypass the impedance rollers and magnetic pickup of the reproducer, can receive a deep gouge rather than fine scratches. Damage to optical-track prints is due to misalignment of the film path rather than any defect of the penthouse attachment. Guide-Roller Adjustment Installation supervisors have been known to overlook the fact that different types of upper-magazine firevalve boxes and different makes of projector mechanism may require special film-guiding rollers to be used in the penthouse reproducer to prevent the film from rubbing against the rough edges of the metal casing when entering or leaving the reproducer. Omission of the rollers may make it impossible to run optical-track prints Clayton Bali-Bearing Even Tension Take-Ups For all Projectors and Sound Equipments ALL TAKE-UPS WIND FILM ON 2, 4 AND 5 INCH HUB REELS. SILENT CHAIN DRIVE THE CLAYTON REWINDER FOR PERFECT REWINDING ON 2000-FOOT REELS. CLAYTON PRODUCTS CO. 31-45 Tibbett Avenue New York 63, N. Y. straight down through the penthouse reproducer without scratching the film. In a few instances even film threaded up for magnetic reproduction rubs against something and suffers serious abrasion. It's up to the projectionist to insist upon immediate correction of a film path so far out of line that the film rubs against surfaces that will scratch it Refrigerated Film To the Editor of IP: The following question has been on my mind for several months, and I'll not be satisfied until I receive an authoritative answer: Have refrigerated films ever been known to buckle? This is a film buckling period, and I wonder if anyone else has observed the following. Chilled film right off the truck comes from the projector lukewarm after showing. After the second showing of the same film, it comes from the projector just plain hot, say 40 or 50 degrees warmer than the first run. It is my opinion that it would be a simple matter to keep our prints in a little freezer when not in use. What do you think of that? By the way, thanks for your article on matching projection optics (page 13, January issue). You can't review a subject like that too often. Al Kuiper Terrace Theatre Robbindale, Minn. Comment: "Refrigerated" prints absorb moisture from the atmosphere, and this moisture is very likely to condense and spot the emulsion of the films. When moist film is projected, the combination of intense heat and moisture usually results in buckling. If the buckling is severe, as when high arc amperages are employed, the film may become permanently warped. Raw stock comes from the manufacturer in tightly sealed cans, and is thus well protected from moisture. But the film must be allowed to warm up above the dew point of the air before unsealing the cans, otherwise condensation and film spoilage may occur. Processed film — particularly theatrerelease prints — are usually stored in the open, or in unsealed cans and shipping cases. When films which are exposed to moist air are chilled, the gelatine emulsion becomes saturated with moisture, or even spotted with tiny water droplets. Reels of film stored under these condi for VistaVision, CinemaScope Rce-CoRED For DRIVE-INS & THEATRES with HUGE, WIDE AREA SCREENS • CARBONS, Inc.BOONTON, N.J 32 and all other Wide-Screen Presentations INTERNATIONAL PROJECTIONIST • March 1956