The DARKROOM COOKBOOK, Third Edition

Monobath Film Developing 55
possible to obtain a wide gamma range without loss of fi lm speed by simply varying the hypo
(or salt) content. In Crawley's FX 6a, the use of 70.0 to 125.0 grams of hypo is recommended
to increase or decrease the contrast of the fi lm. Less hypo results in higher contrast. Similar
variations in the amount of hypo can be made to the other formulas. The rate of fi xation is
also infl uenced by the amount of hypo.
The speed of development can usually be controlled by the alkali content. Sodium
hydroxide is used in the monobath formulas given in the Formulas section. Most monobaths
which use hydroxide will develop medium speed fi lm in 3 minutes at 75F/24C. Testing is
advised.
Working with the two variables of hypo and accelerator, monobath formulas can be modifi
ed for different fi lms. In fact, Grant Haist, in The Monobath Manual, has concluded that no
monobath can be formulated that will work equally well with all fi lms. However, it is possible
to design a monobath for individual fi lms that will produce results comparable to normal
processing. If you have an interest in monobaths, you may want to experiment and create
a specially balanced formula for each group of similar emulsions (for example, modern fl atgrain
emulsions, conventional emulsion fi lms of similar speed, etc.).
The following variations in monobath formulation and processing conditions, summarized
by Haist, may be used to modify the results.
To increase contrast and emulsion speed:
1. Raise the pH.
2. Increase the concentration of the developing agent.
3. Reduce the concentration of the fi xing agent.
4. Raise the processing temperature.
5. For more contrast, increase the concentration of hydroquinone.
6. For more speed, increase the concentration of Phenidone.
To reduce contrast or emulsion speed:
1. Lower the pH.
2. Increase the concentration of the fi xing agent.
3. Increase the salt content or viscosity.
4. Use more vigorous agitation, increasing the rate of fi xation (this may not be possible with
in-cassette processing, see below).
IN-CASSETTE PROCESSING
Processing 35 mm fi lm inside the metal cassette it comes in was originally described by
Eastman Kodak. It should only be used with a 24-exposure roll or smaller, as a 36-exposure
roll does not have enough room for the solution to fl ow evenly.
Other than the fi lm, all that is needed is a household water glass or beaker for the monobath
and washing, chemical resistant gloves, and an agitation rod. To make an agitation rod,
pick up a 3/8-inch wooden dowel at a hardware store. Cut off about six inches and notch one
end with a penknife or a hand saw. The notch should fi t over the notch in the fi lm spool.