Pyrocatechol Compensating Developer

Used as a tray developer it compensates for extreme contrast. When used as a tank developer it has pronounced compensating effect for errors of exposure.

Extended exposure time is not required. Although it is not a “true” fine-grain developer it produces a fairly fine grain. It gives a maximum of shadow detail in negatives expose with artificial light. Regular agitation is necessary in a tank as well as in a tray.

The solution for use is composed of the two following stock solutions:

Solution A can be kept is stored in a brown bottle filled to the top. Solution B will keep for about two month in the same conditions.

For use in a tank take 500 mililiters of water plus 12 mililiters of Solution A plus 7 mililiters of Solution B (12:7:500). Develop for 12–16 minutes.

Since the most delicate shadows parts of the negative appear rapidly, it is advisable to decrease the developing time if negatives of lower contrast are desired. Owing to the small amount of sodium sulphite used, the developer has a tanning effect, producing negatives of a brownish color.

Used developer must be discarded.

If larger negatives showing extremely high contrast are developed in a tray, processing may be stopped after 8–10 minutes. Alternatively, negatives of high contrast can be obtained by developing up to 30 minutes.

As a general purpose tray developer it is highly economical and produces negatives of a well-balanced gradation with maximum detail in the shadows and suppresses excessively bright highlights.

A suitable solution is 100 mililiters of water plus 4 mililiters of Solution A plus 3 mililiters of Solution B. The average developing time is 10–12 minutes, which will be sufficient to produce well-balanced negatives.

Note: Negatives developed with pyrocatechol cannot be reduced or intensified as it tans the emulsion.

The formula has little tendency to form a sludge and has also a very low fog level with forced development.