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

1. A substantial concentration gradient exists through the emulsion. 2. The diffusion time through the emulsion is not abnormally high. 3. The time of chemical reaction is not abnormally long. 4. The emulsion is relatively thin. If any one of these aforementioned quantities becomes dominant, so that it becomes the main controlling factor of the photographic process, the improvement due to the application of turbulent fluids will be considerably reduced. Conversely, any reduction in these factors will increase the time gain obtained by the application of turbulent fluids. Consequently, the gain resulting from the application of turbulent flow will, in general, increase as the speed of photographic processing is increased. Therefore, greater improvements can be expected from the application of turbulence if more concentrated, highertemperature developers are used with thinner emulsions. Description of Equipment In order to perform satisfactory experiments in which quantitative data could be obtained with a reasonable degree of consistency, a turbulent processing unit had to be constructed which would permit changing the desired variables while leaving all other parameters constant. The original processing unit which had been constructed during early experiments (see Fig. 1) was not suitable because it did not permit switching fluids. Consequently, the film samples had to be removed from the chamber by hand and be immersed in a fixer or stop bath for the processing. This hand operation varied too much in time from one sample to the next and consequently a wide spread in the data was obtained. It was, therefore, decided to build an equipment to conform to the following specifications : 1. The machine will permit the rapid introduction and withdrawal of a film strip approximately 35 mm wide and 6? in. long on which a photographic wedge has been exposed. 2. The machine will permit the introduction of different channel diameters over the film so as to permit the study of different Reynolds numbers and different diameters. 3. The machine will permit the introduction of several fluids in rapid succession. 4. Timing will be accomplished electrically and automatically so as to eliminate human error. 5. At least one of the fluids will be variable over a wide range in pressure and volume. 6. Provisions will be made for thermostatically controlling the temperature of the solutions. 7. Volume flow, temperature and pressure of the fluid will be measured. As a result a turbulent processing machine was designed as shown in Figs. 2 to 8, inclusive. This machine consists of three basic units as follows: 1. Base frame containing motors, pumps, drip tank, variable speed drive, fluid tanks and cooling system. 2. Turbulent developing chamber with intake, exhaust and by-pass valves. 3. Control panel containing motor and valve timing controls. The base frame (see Figs. 2, 5 and 6) is of angle-iron construction of dimensions 60 X 30 X 42 in. Four 1-hp, 1725-rpm, 220-v, 3-phase, Ideal motors are mounted on the lower level of the base frame. Each of these motors drives an Eastern Industries Model Z, flange-mounted, 304 stainless-steel pump through belts and pulleys. The pumps are mounted several inches above the motors, which permits the changing of pulleys so as to get different operating speeds of the pumps. In addition, a Worthington All-Speed drive was installed between one of the motors and the pump to permit continuous varia Katz and Esthimer: Turbulent Fluid Processing 111