The DARKROOM COOKBOOK, Third Edition

136 THE DARKROOM COOKBOOK
Refl ection
The second method is by refl ection. Some photographers claim this is a more accurate
method. To use this method hold the fi lm at least 3 feet from the safelight and look at the
base side with the light refl ected off of it not through it. Once again, judge the highlights
which are the densest part of the fi lm. When the highlights appear dense but not completely
black development is complete.
Both the transmission and refl ection methods work equally well with any panchromatic fi lm.
Using either method, as many sheets of fi lm as can be safely handled at once can be developed.
When a fi lm is fully developed it should be moved into a holding acid stop bath or running-water
rinse where it can be left until the other fi lms catch up at which time they can all
be moved to the fi xing bath.
DESENSITIZERS
Desensitizing is a process that reduces the light sensitivity of emulsions so that they can be
developed in comparatively bright light. Unfortunately, most of the desensitizers once in common
use, such as Aurantia, Methylene Blue, Toluylene Red, and Amethyst Violet, don’t work
well with modern emulsions.
Phenosafranine was the fi rst viable desensitizer and originally appeared on the market
as Pinasafrol and Desensitol. Although phenosafranine can be used alone, diluted 1:10,000
with water, a better choice for modern MQ developers is Basic Scarlet N, a combination
of phenosafranine and chrysoidine, two commercially available dyes. Basic Scarlet N is
more effi cient than phenosafranine alone and has greater keeping properties (Formulas:
Miscellaneous).
The major drawback to both phenosafranine and Basic Scarlet N is that they stain everything.
They can also cause excessive fog when used with pyro developers.
The disadvantage of the strong staining properties of phenosafranine and its allied compounds
soon led to the discovery of other desensitizers that do not stain to the same extent.
Pinakryptol Green was the fi rst to receive wide application. In solution, it has a dark green
color and the slight coloration of the fi lm usually disappears with washing.
Pinakryptol Green was introduced in the 1920s by Dr. Köenig of the Hoechst Dye Works
in Germany. It was originally available only as a proprietary powder from Agfa-Ansco. At one
time, Pinakryptol was available in three formulas: the original green, then yellow, and fi nally
white. Green was the least effective and could cause staining with some MQ developers, but
could be used as either a forebath or mixed directly into most pyro developers. Yellow is
more active for reducing panchromatic sensitivity and more compatible with MQ developers
but can only be used as a forebath, as it is destroyed by sulfi te.
White was sold in tablet form, and was meant to be used in the developer. White had the
advantage of being compatible with both pyro and MQ formulas. The only Pinakryptol still
available is Yellow and it is diffi cult to obtain.
There is still one commercially available desensitizer available. It is known as De-tec®
and marketed by Antec (see Resources).