Society of Motion Picture Engineers : incorporation and by-laws (1928)

396 Transactions of S.M.P.E., Vol. XII, No. 34, 1928 An examination of negative film which has been especially treated to render it non-static shows that the film base surface has been altered in its electrifying nature so that it tends to electrify positively with a charge approximately the same or somewhat greater than that of the emulsion surface. While this treatment creates a large safety factor as far as discharges between the opposite sides of the film are concerned, the film as a whole still has a tendency to electrify when breaking contact with rollers or encountering friction in a camera. It is imperative to maintain the original moisture content of the film up to the time of exposure in the camera in order to provide leakage paths both through the film and along its surface for the dissipation of such charges as may be generated by some part of the camera.1 The foregoing discussion of the effect of moisture on perforation pitches, on tensile strength and wearing qualities, and on static discharges covers some of the important characteristics of motion picture film which are affected by moisture. There are others of more or less importance, such as photographic keeping quality, permanency of latent image, mildew, or bacterial action, etc. Some of these things require low moisture for optimum results while others require high moisture. Fortunately there is a satisfactory mean which the manufacturer has found through much research and experience. He spares no expense to pack every roll of stock under the most ideal conditions that science and engineering can create, and with reasonable precautions in the storage and handling of film it will give the service that is expected of it. 1 Static Markings on Motion Picture Film by J. I. Crabtree and C. E. Ives, Trans. S.M.P.E. No. 21, 1925, p. 67.