c. Compensation for Aging. When solutions stand for some time without
use, such as over a weekend, it is necessary to make allowance for the
decrease in activity of the developers. For a two-day shutdown, try adding
developer replenisher at the rate of three percent of the developer tank
solution (1 gallon solution - 3.84 ounces).
d. Special Treatment Required for Bleach Solution. The efficiency of
the action of the bleach depends upon a certain amount of aeration of the
bleaching solution.
The best way to achieve this aeration is to use
airburst agitation. An alternate method is to introduce air from a separate
compressed air supply, such as the Kodak gas distributor sparger.
This
should be done for about 30 minutes before each process at a valve pressure
of about 2 1/2 pounds per square foot. Since it is not possible to over-
aerate the bleach, it is recommended that low-level aeration continue
throughout the day.
13.
Chemical Storage.
Even well-mixed and properly replenished solutions will become exhausted
with age. Ensuring proper control of your chemistry includes discarding old
chemistry. Figure 2-7 gives the useful life of C-41 chemistry.
Figure 2-7.
Useful life of C-41 chemistry
14.
Quality Control.
After mixing color processing chemistry and prior to film processing, an
analysis may be made of the solutions.
This analysis would require the
performance of the following tests: determine the specific gravity (SG),
determine the potential hydrogen (pH), and run a sensitometric check.
2-15
SS0514
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