Journal of the Society of Motion Picture and Television Engineers (1950-1954)

tion to other improvements which can be obtained by operation at higher temperatures or higher concentrations. The theory further indicates that the time factor of 2 will considerably increase when the entire photographic process is speeded up. The speeding up of the photographic process, in general, might be obtained as follows: 1. Operation at elevated temperatures (approximately 85 to 100 F). 2. Operation with more concentrated chemical solutions (both developer and fixer). 3. New chemical compositions such as mono-bath or other chemicals which may have harmful effects when used under conditions of no agitation or constant agitation but may be well suited under conditions of turbulence. 4. The application of electric fields to increase the ion transfer occurring in the photographic process. 5. The use of developing or fixer solutions in which the chemicals making up the composite solutions are passed over the film in succession without having previously been mixed. For instance, a developer solution will normally consist of various constituents such as alkali, developing agents, reducing agents and retarder. It may be possible that a greater increase in the rate of developing can be obtained by passing through alternate shots of various submixtures of these agents of different balance at intervals of approximately one second. In this way it might be feasible to swell the gelatin rapidly first, then rapidly introduce the developing agent which may have a different rate of diffusion than the swelling agent, then give a shot of retarder which again may diffuse through the gelatin at a different rate. As a result it might be possible that the sum total of chemicals deposited in the gelatin is identical whereas the total rate of transfer is increased because of the increased concentration of each of the components. Acknowledgments Most of the work described in this paper was done in cooperation with the Air Forces Air Materiel Command, Wright Field, under contract with the Optical Research Laboratory, Boston University, with the assistance of D. E. Macdonald, R. C. Gunter, Jr., H. Gewertz, R. Dussault, H. Howell and Capt. F. A. Yochim. We are also indebted to personnel of the Photographic Laboratory at Wright Field, Maj. J. Jackson, Capt. E. Conway, J. C. Lewis, W. Levison, J. Phelen, I. Weisman and Dr. M. Nagel, who assisted in the setting up of the design objectives of this program. The assistance of W. Marvin, J. F. Moore and E. P. Cignoni, who helped in the design of the equipment and the performance of the experiments, is gratefully acknowledged. We are also indebted to Prof. J. Kaye of M.I.T., for his valuable consulting services. References 1. L. Katz, "Controlled processing of film using turbulent flow phenomena," Phot. Eng., 2: No. 3, 89-101, 1951. 2. Final Engineering Report on Study Program Leading to Design Data for a High-Speed Film Processing Unit, Raytheon Mfg. Company, January 1, 1952. 3. L. Katz, "Ultrarapid drying of motion picture film by means of turbulent air," Jour. SMPTE, 56: 264-279, Mar. 1951. Discussion Paul Ireland (EDL Co.) : You referred to the diameter — is that the equivalent diameter? You don't have an actual cylindrical tube. You have a rectangular cross section. Is there a mathematical equivalent to the diameter? Mr. Katz: Yes, we use the equivalent diameter De which is given by the following equation : 2Z):Z)2 where DI and D2 are the sides of the rectangle. This equivalent diameter is 128 February 1953 Journal of the SMPTE Vol. 60