The motion picture projectionist (Nov 1930-Oct 1931)

36 Motion Picture Projectionist December, 1930 Review How to Prevent Film Mutilation By Eastman Kodak Company 0 H.I L 1 J . Ik M\ ^B0t 1 IF II ON some projectors these rollers are adjustable by means of a collar and set-screw, while on others there is no regulating device. Certain manufacturers using the latter type, rely on the proper centering to be made at the factory, nevertheless there are times when an adjustment is found to be necessary and it is very important that great care should be used in lining up the guide rollers with the intermittent sprocket, otherwise damaged perforations will result. See Figures 5 and 6. If these rollers bind, the face of the rollers will develop ridges which will roughen the edge of the film as shown in Figure 7. It is also well to examine new rollers closely as in some cases they are received from the factory in a semi-finished condition, and have rough faces against which the edge of the film comes in contact. Friction Take-Up The take-up adjustment should be checked up closely from time to time. An excessive pull can always be detected by the film making a "singing" sound at the take-up sprocket. The sprocket, of course, acts as a holdback or brake and puts a strain on the film, when starting on a small hubbed reel. This is sometimes enough to Fig. 5 cause very severe damage to the upper side of the perforation. Figure 8 shows the sprocket damage resulting from a tight take-up. Proper setting of the spring is a simple matter and care should always be taken to keep the friction disc, whether leather, cork or fiber, absolutely free from oil. Contrary to some opinions oil will not cause smoother operation in a case of this kind, but will really create a certain amount of suction which in turn results in an uneven, excessive pull. Tension on Upper Magazine Shaft or Spindle Some widely used makes of projectors have an adjustable spring FIG. 6. This guide roller may be adjusted by loosen, ing the set screw in collar 2 and then after centering tightening the screw. Great care should be taken not to "spring" the shaft. FIG. 7. The arrow shows where the. film edge hag been chewed away by bent reels or imperfect alignment of the upper magazine. tension on the upper magazine shaft or spindle. Proper adjustment of this spring is important. If set too loosely, the film will come from the feed roll with a jerky motion. This is especially noticeable if used with a bent reel, which is bad for any, film, particularly film which is in a driedout condition or badly worn. If the tension is too tight the effect would not be noticeable on a full reel of film, but the tension on the last 50 or 75 feet would be sufficient to cause serious perforation damage when a small hubbed reel is used. It is not uncommon for the film to break under this strain. Sprocket Idlers All sprocket idlers must be properly adjusted. If set too far from the BLUE SEAL HEAT RESISTING IMPROVED FILM TRAPS FOR SIMPLEX PROJECTORS MADE OF AN IRON ALLOY Guaranteed not to Warp under the intense heat of the Arc Spot. A necessity for the Perfect Projection of "Sound'* Pictures B-16 Film Traps with Sliding Double Round Corner Apertures, one Aperture for Disc and Silent Film and one cut Proportional for Movietone Film to be used with our Adaptors .... $30.00 B-17 Sliding Double Aperture Plate 6.00 B-24 Film Trap with individual mats for silent, movietone and magnascope effect. Traps complete with all mats 30.00 B-20 Master Plate to hold mats stationary 1.50 B-21 Standard Aperture with Square Corners 1.50 B-22 Proportional Movietone Aperture with Square Corners 1.50 B-23 Blank Mat (CAN BE CUT ANY SIZE APERTURE).... 1.50 Manufactured by BLUE SEAL PRODUCTS CO., Inc. 262 Wyckoff St. Manufacturers of Motion Picture Accessories Since 1913 Brooklyn, N. Y.