Agitation. If a film is placed in a developer and
allowed to develop without movement, the chemical
action soon slows down because the developing agent
in contact with the surface of the emulsion becomes
exhausted and bromide (a restrainer) is released as a
by-product. When the film is agitated, however, fresh
solution is continually brought to the surfaces of the
film, and the rate of development remains constant.
Therefore, agitation also has an important effect on the
degree of development. An even more important effect
of agitation is it prevents uneven development. If there
is no agitation, the exhausted solution that became
saturated with bromide from the emulsion may flow
slowly across the film from the dense highlight areas
and produce streaks. Constant agitation is usually
recommended for the first 30 seconds of tank
development and for the entire developing time when
the film is being processed in a tray. After the initial
30-second agitation cycle, the film should be agitated
for 5 seconds, once every minute during the remaining
time.
The time, temperature, and amount of agitation
required for a film/developer combination are
recommended by each manufacturer of film or
developer. These recommendations are in the
instructions that accompany the film or developer.
Another reference source is the Photo-Lab-Index.
There are three different methods of processing film
by hand. These are as follows: the tray, the sheet-film
tank, and the roll-film tank. Each method is discussed
here with an example of the darkroom arrangement
used.
TRAY PROCESSING
The tray method is used primarily for processing
only a few sheets of film. With a lot of experience, you
can process as many as 6 to 12 sheets of film in a tray
at one time. You will find it easier to work with only a
few sheets of film at a time, and repeat the process, than
to start all the sheets at the same time and damage them.
The tray processing method described here has
proven satisfactory under most conditions for
processing one sheet of film at a time. You should use
this method as described and develop the necessary skill
using this procedure before you attempt to use
variations.
The trays should be considerably larger than the
film being processed; for example, 4x5 film should be
processed in 8x10 trays, 8x10 film in 11x14 trays, and
11x14 film in 16x20 trays. Ideally, the trays should be
arranged in a shallow sink that contains temperature-
controlled circulating water. The trays should be
arranged with the developer to your left as you face the
trays. The stop bath goes next to the developer, followed
by the fixer and the wash tray.
In all Navy imaging facilities, it is standard
procedure when processing film (or prints) by hand to
work from left to right.
Rinse the trays with fresh water as a precaution
against contamination, and prepare the solutions. When
the solutions are ready, place the exposed film holder to
be unloaded on a clean, dry area of the workbench near
the developer. Set the timer for the correct developing
time, and place it in a convenient location near the
processing solutions. Then, if you are processing
panchromatic film, turn out all the lights. If you are
processing monochromatic or orthochromatic film, you
can use a suitable safelight.
Remove one sheet of film from the holder and
submerge it quickly, emulsion-side down, into the
developer. Then immediately turn it over (emulsion-side
up) and slide it back under the surface of the developer
quickly, and agitate it vigorously to eliminate possible
air bubbles. The surface of the film must be wetted
quickly and evenly; otherwise, developing marks may
result. Start the timer just before the film is placed into
the developer.
During tray development, the tray should be rocked
continuously to provide constant agitation. Be careful
that the tray rocking is not too fast and that it is varied
at intervals; for example, first front to back, and then
side to side to avoid patterns of uneven development
caused by regular waves.
CAUTION
Do not allow your fingernails to touch the
film emulsion at any time.
Tray development involves constant agitation, and
development time is usually about 20 percent less than
if the same film were being developed with intermittent
agitation. When tray agitation is done very slowly, the
agitation should be considered intermittent and the
developing time adjusted accordingly.
When the timer rings, remove the film from the
developer, drain it from one corner, and submerge it in
the stop bath. Agitate the film in the stop bath for about
5 seconds; then transfer it to the fixer. You must agitate
10-16

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