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TWO SOLUTION PROCESSING 377
minutes) have been quite advantageous with EK 5203 dupe negative film for making intermediate dupe negatives between the original reversal and the fine-grain release print. Other reducing agents also will be found advantageous. Graininess is reduced materially by selecting the right kind of developer bath and by reducing the developing time (with compensating increase of dupe negative exposure) thereby taking advantage of the difference between the graininess developing time characteristics of negatives and positives. There is still much to be done in reducing the graininess of release prints; the dupe negative will provide much of the opportunity.
Two Solution (Reversal) Processing
For reversal developing, a few more processing steps must be added.
A typical procedure would be :
1.
A pre-hardener
2.
A developer
3.
A water rinse
4.
A bleach
5.
A clearing bath
6.
A second exposure — provided by a relatively bright lamp (not
controlled)
7.
A second developer
8.
A water rinse
9.
A fixing bath
10.
A wash
11.
Drybox
Typical formulas used are listed in Table XXI.
The fixing bath (9) may be the same as that used with negative or positive development ; the EK F-25 bath listed previously is suitable.
As a practical matter, laboratories that can afford to do so use separate developing machines for the different kinds of processing. Where this is not possible the developer and the hypo (or other chemicals such as those used for reversal development) are pumped out of the machine to storage tanks for future use. The machine is then cleaned out and the different developer or other chemicals pumped in. The practicability of this method depends upon the design of the machine itself. The problem of draining is similar to that of draining an automobile radiator. If the drain is not at the lowest point in the system with sufficient grade to cause