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1949 COLOR PROCESSING CONTROL 13
speed over months of operation. The exact effects produced by photographic variations differ somewhat among different emulsions depending on the exact color balance of the emulsion. In general, variations of color developer affect the heavier densities to a greater degree than the lower densities whereas variations in first developer cause deviations in the over-all speed and balance of the film.
Relatively large quantities of replenishers are utilized in most cases. In the first developer, the rate is high to avoid build-up of bromide in the developer. In the color developer, replenishment rate is high because the replenisher solution is nearly as concentrated as possible. Bromide accumulates so slowly in the color developer it is necessary to add it in the replenisher solution to maintain the original amount. The short stop and hardener solutions are replenished at these high rates to prevent excessive accumulation of contaminants. No continuous replenishment is used with the bleach and fixing baths. The bleach is shifted to a separate tank, rejuvenated with bromine and after adding additional salts to make up for those lost by dilution, is returned to the machine tank. The fixer is used to exhaustion, then dumped into a large crock for sulfide recovery of silver.
2. Detailed Replenishment Procedure
The replenishment rates given in this paper are based on the rates used for the Ansco 16-mm and 35-mm developing machines. Other machines may perform best with slightly modified conditions or formulas. In fact, replenishment rates normally vary slightly during routine operation of any single machine. However, the formulas and rates of replenishment listed provide a close approximation of the requirements of any machine and are to be recommended as a starting point.
The developer replenishers were formulated using solution-analysis techniques and when used in combination with photographic and analysis tests have maintained developers over periods of months in the Ansco laboratories.
It is recommended that 3.5 to 5.0 milligrams per liter of potassium iodide be added to fresh tanks of No. 502 first developer. Analysis data indicate that the normal iodide-equilibrium ranges around these figures, subject somewhat to the exposure level of the film processed.
Changes in first developer activity are evidenced by over-all speed changes of the complete film. The exact color-balance differences