International projectionist (Oct 1931-Sept 1933)

14 INTERNATIONAL PROJECTIONIST March, 1933 change, it is desirable that the laboratory treat it so that: (1) The pulling or straining of perforations, due to deposits of emulsion on the tension shoes or aperture plate of the projector be eliminated. (2) The emulsion be so toughened as to resist scratching of the surface of the film as far as possible. (3) The warping and buckling of the film, caused by the heating of the gelatin by the projection lamp, should be reduced as far as possible. (4) The pliability of the gelatin and its binder should be as permanent as possible, so that the useful life of the film may be made at least equal to the booking period. Capacity of Reels A standard size of reel, agreed to and used by both the exchanges and projectionists, must be adopted for the good of all concerned. The mounting of film in the exchanges on 1,000-foot reels for transportation, the subsequent transferring of the film to reels holding from 1,500 to 3,000 feet of film in the projection room, and the re-transfer to the original 1,000foot reels for return to the exchange represents a great deal of lost motion. Needless time and effort is spent by the projectionist in making such changes. A like amount of time and effort is lost in the exchange inspection room in checking the correctness of the footage and of the heads and tails of the reels. A large amount of film footage is lost because of this practice, and either all film should be mounted on large reels in the exchanges, or projectionists should be forced to discontinue the practice of mounting two or more reels of film on one large reel. From an exchange standpoint, the 1,000-foot reel is far more desirable, owing to the greater ease with which it can be handled and the greater ef ficiency with which it can be inspected. The tensile strength of new film and its elongation properties will permit reels to be doubled under proper working conditions without damaging the film; but when the film has become seasoned the perforation area admits of less elongation than the center of the film and is, therefore, subjected to the entire strain of the traction load of the film in the upper and lower magazines. The braking surface in the upper magazine, for properly controlling the feed of the film when the double reel is full, causes a tension to be applied to the later footage of the reel that often is greater than the elongation of the perforation area permits. The perforations, as a result, break down. Proper Tension In the lower magazine, improper adjustment of the friction drive or the take-up will often cause a similar condition in the early footage of a reel. The variation of the shaft speed of the take-up, caused by the increasing of the circumference of the reel as footage is added to it, is compensated for in a friction drive that must be precisely adjusted to drive the take-up steadily when the reel is filled. The friction required to cause such a steady drive of a full reel is greater than that required for the incomplete reel; whence there results a tendency, in the early footage, for the reel to take the film faster than it is fed out by the lower sprocket. Insufficient tension on the friction drive of the take-up will halt the loaded reel momentarily, thus creating a slack in the film between the take-up reel and the lower sprocket. This slack permits the take-up drive to operate under no load, and the reel accelerates ahead of the feed of the lower sprocket, tearing the film at the SINGLE REELS WITH 5-INCH HUBS Excerpt from Report of S.M.P.E. Committee on Care and Development of Film (Exchange Practice Sub-Committee) 'T^ HE sub-committee believes that it would be well for the exchanges to consider mounting all film on 1,000-foot reels having 5-inch hubs, instead of on the 1,000-foot reels with 2-inch hubs now universally used. Because of the larger hub, the reel can be made considerably stronger, and a more positive stand can be consistently taken against doubling of reels by projectionists. Such a reel would vacate two of the faults of the reel now used by exchanges that most projectionists offer as reasons for doubling: namely, a uniform reel size for use in the upper magazine, and a reel with a 5-inch hub for the take-up in the lower magazines . . . The cost of a strongly built reel with a 5-inch hub would be greater than that of the reel now used; but it is the opinion of the sub-committee that this difference in cost would be more than offset by the probable saving of time of inspection, the elimination of doubling, and the loss of film at the beginnings and ends of reels. lower sprocket when the end of the slack is reached. Suggesting a remedy for this, the sub-committee believes that it would be well for the exchanges to consider mounting all film on 1,000-foot reels having Sinch hubs, instead of on the 1,000-foot reels with the 2-inch hubs now universally used by the exchanges. Cure for Doubling? Because of the larger hub, the reel can be made considerably stronger, and a more positive stand can be consistently taken against the doubling of reels by projectionists. Such a reel would vacate two of the faults of the reel now generally used by the exchanges that most projectionists offer as reasons for doubling reels : namely, a uniform reel for use in the upper magazine, and a reel with a 5-inch hub for the take-up in the lower magazine. This size of reel could be used without materially changing the present shipping cases, vault racks, or equipment in the inspection rooms. The cost of a strongly built reel with a 5-inch hub would be greater than that of the reel now used; but it is the opinion of the sub-commitee that this difference in cost would be more than offset by the probable saving of time of inspection, the elimination of doubling of reels, and the loss of film at the beginnings and ends of the reels. Cleaning of Film A film record card should be made out for each print, on which is kept a record of the condition of the film, its location while in the vaults, full data on playing dates while out of the house, the inspector's initials, and the date of each inspection. Film should be graded as to its condition in the following manner: No. 1 : good in every respect. No. 2 : good ; film damaged slightly. No. 3 : film in poor condition. No. 4 : junk film. Film can be satisfactorily cleaned by cleaning machines now on the market. If done in the exchange, it is impracticable to attempt to clean film by hand. All cleaning fluids should be non-inflammable and uninjurious to celluloid or gelatin. Carbon tetrachloride can be used satisfactorily for cleaning film, as can trichlorethylene, but the use of either requires proper ventilation. For exchanges that operate their own cleaning plants, the sub-committee recommends the use of a machine that submerges the film in the cleaning fluid, cleans the emulsified dirt and oil from the film by passing the (Continued on page 28)