4. Type of developer. The type of developer chosen for processing your
film is dependent on the film type and the desired final product. To make
an informed decision you must be familiar with the characteristics of
developers and film.
a. The initial phase of development affects the density of highlights
and shadow areas to approximately the same degree. As the developing action
continues, however, highlight areas of the negative, or shadow areas of
prints are rendered more dense. Therefore, the developing action should be
stopped when the contrast between the light and shade tones is most
satisfactory. Actually, since development is done in total darkness,
several processing "runs" of test film may be necessary to determine the
optimum developing time.
b. The speed of the developing action is determined primarily by the
activity of the developer. However, the film type is also a factor.
c. There are several types of developers, and each differs in activity
and provides different qualities of development. In selecting a developer,
consider the type of film, the conditions under which it was exposed, and
the results desired. Accordingly, select a low working developer for
negatives requiring a low or medium degree of development, and an active
developer to obtain a high degree of development. For example, aerial
photographs produced under poor light conditions require a very vigorous
developer to bring out as much of the image as possible, while portrait
negatives usually call for a much less active developer.
d. Listed below are a few developers currently available and a brief
description of their characteristics:
5. Developing temperature and time. When developing any type of film,
there are two major factors determining the final outcome of your negative,
the temperature of your developer and the time (minutes) you keep the film
in the developer.
a. The normal processing temperature is 68 degrees Fahrenheit (20
degrees Celsius). If the developer is above 75 degrees