(4) Fixing. The film is then placed in another chemical, sodium
thiosulfate, which renders the unexposed and undeveloped silver halides
(5) Washing. A water wash removes all chemicals, water soluble salts
(6) Wetting agent. A wetting agent consisting of a high quality
detergent that replaces the water particles allowing for faster drying and
the reduction of water spots during drying.
(7) Drying. The film is dried which results in a "negative". A
negative is an image of the subject photographed in which the various tones
Figure 17. Developing process
b. Film handling is complicated by the fact that the emulsion is
sensitive to light and must be protected until fixation is well under way.
Observe the following procedures when you are handling film:
(1) Remove the undeveloped film from its original wrapper in total
darkness. Failure to do this will cause the film to become fogged and
(2) Always handle film gently and by the edges.
(3) Never touch the film surface.
(4) To prevent defects from forming during processing, agitate the
film so that the solutions can act uniformly over its' entire surface.