The DARKROOM COOKBOOK, Third Edition

42 THE DARKROOM COOKBOOK
TYPES OF DEVELOPERS
Divided Developers
Divided developers are used for what is known as either divided or two-bath development.
Divided development allows a photographer to expose roll or sheet fi lm under many different
and diffi cult situations and still create printable negatives because of the compensating action
inherent in the process.
Divided development has a number of secondary advantages:
● It produces even, consistent development.
● Development takes place primarily on the surface of the fi lm so there is less halation and irradiation,
resulting in the best possible sharpness.
● Depending on the choice of developing agents, there can be little or no loss in emulsion sensitivity;
often sensitivity is increased.
● Temperature variations have minimal effect on contrast and density.
Another advantage is that the cost of developer per roll of fi lm is much less than with
single-solution developers. A safe number of rolls of fi lm to develop using one liter of the
fi rst bath is twenty, as long as the solution is not contaminated or does not oxidize. The second
bath, which contains the less expensive chemicals, should be discarded after processing
ten rolls of fi lm. Divided development can be used for all fi lms except document fi lms (for
example, Rollei ATP®).
When formulating a divided developer the addition of sodium bisulfi te to the fi rst bath
will help prevent oxidation. The rule is to make the preservative approximately 20% bisulfi te
(for example, D-23 Divided Developer requires 100.0 grams of sodium sulfi te; instead use 80.0
grams of sulfi te and 20.0 grams of bisulfi te).
Technique of Divided Development In divided development, two separate baths are used. The fi rst bath
contains the developing agent(s), restrainer, and preservative. The second bath contains
the accelerator. The second bath is used to activate the developer. Borax is the least active
accelerator; metaborate is about double the strength of borax; carbonate is about double the
strength of metaborate. Hydroxide is the most active of the alkalis and the least controllable.
Film is placed in the fi rst bath where the emulsion absorbs the developing agent. Because
the pH is low, little or no development takes place. The fi lm is then transferred directly to the
second bath without rinsing.
Development takes place in the second bath until the developing agent is exhausted. The
shadow areas, where less exposure to light has been received, will continue to develop even
after the developer has been exhausted in the highlight areas. The result is the compensating
action mentioned earlier.
Do not use a presoak and do not rinse between the fi rst and second baths. After the second
bath, use a water rinse or place the fi lm directly into the fi xer.
Although agitation is not as critical as with single solution developers, it should always
be gentle. In the fi rst bath, agitation may be intermittent after continuously agitating for the