Operating Manual

87
Developer
Development fog, graininess and contrast are dependent on the type of developer,
which is preferably made up to suit the film used.
If a concentrated manual developer is used, for example G128 made by Agfa, and the
developer tank has a capacity of, say, 25 litres, then all to do is pour 5 litres of the con-
centrated developer into the tank and add 20 litres of water (ratio 1 part of concentra-
te to 4 parts of water). G128 developer is also used as a replenisher, in which case 3
parts of water are added to 1 part of concentrate.
Fixer
Fixer too is supplied as a concentrated liquid (G328). The same instructions as for pre-
paring developer apply here.
Developing times and bath temperatures
The film is clipped on or slipped into a frame, depending on the type of frame, and hung
in the developer tank. As soon as the film is submerged in the developer, the darkroom
timer is set for the required number of minutes. The optimal developing time is the time
at which the most favourable “contrast to fog ratio” is achieved. Minor deviations from
the correct exposure time may be compensated by adjusting the developing time.
The recommended developing time for Agfa films in G128- manual developer is
5 minutes at 20°C. In the automatic process using G135 developer, the developing time
is 100 seconds at 28°C. Deviating from the recommended developing times and
temperatures will almost always lead to reduced image quality (e.g. increased coarse-
graininess).
Raising the tank temperature will speed up the development process as table 1-10
shows, but the developer will oxidise more rapidly. Should it not be possible to achieve
a bath temperature of 20°C, the following developing times can be used at the
temperatures as indicated in table 1-10. This applies to all D-type films.
The temperature of the developer shall never be less than 10°C, but is preferably
higher than 18°C to obtain optimal image contrast. It is best to always maintain the
same developing conditions, so that the exposure technique can be matched to these
and uniform results obtained.
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Another method is to place an unexposed film on the workbench and cover part of it up
with a sheet of cardboard, which is then gradually removed so as to produce a series of
different exposures. By developing the film in the usual way, it will then be possible to
see how “safe” the light is, and how long a film can be exposed to it before it exceeds the
maximum acceptable difference in density of 0.1.
Darkroom layout
The darkroom should preferably be divided into a dry side and a wet side. The dry side
will be used for loading and emptying cassettes, fitting films into developing frames and
so on - in short, for all the work that does not allow dampness.
On the wet side, the films will be processed in the various tanks of chemical solution.
For efficient working, and to ensure uniform quality, there should be automatic control
of the temperature of the solutions.
Tanks
In processing tanks used in the manual process, films are held vertically in their frames.
These tanks can be made of stainless steel or plastic. The dimensions of the tank must
be suited to the size and number of films to be processed. There must be a space of at
least 1.5 cm between films. The top edge of the films must be approx. 2 cm below the
surface of the solution.
The wet side of the darkroom will have five tanks, arranged in the following sequence:
1. developer tank
2. stopbath or rinse tank
3. fixer tank
4. final wash tank
5. tank for wetting solution
10.2 Chemicals and film-development
Making-up processing solutions
Nowadays, chemicals are supplied as a liquid concentrate, suitable for the particular
type of film used.
The processing solutions can be prepared either directly in the tanks or in plastic buc-
kets. In the latter case each type of solution must be prepared in a separate bucket,
which is never used for other chemicals.
Temp. °C 18 20 22 24 26 28 30
Time/mins 6 5 4 3.5 3 2.5 2
Table 1-10. Developing time versus developer temperature.