THE PHOTOGRAPHIC PROCESS
Determine the types and uses of chemistry for both black and white and
color; the procedures for processing negatives and prints; and the
procedures for mixing and storing chemistry.
Given information and diagrams on the types of chemistry and procedure for
mixing and storage.
Demonstrate competency of the task skills and knowledge by obtaining a
minimum passing score of 75 percent of the multiple-choice test covering the
preparation of photographic chemistry.
Learning Event 1:
PREPARE PHOTOGRAPHIC CHEMISTRY
1. Chemical reaction.
When an exposure is made, a chemical change takes
place in the light-sensitive silver halides. During this chemical change,
the silver halides suspended in the gelatin emulsion layer produce a latent,
or invisible image.
a. The film is then immersed in a photographic developer. The purpose
of the developer is to continue the chemical reaction that began with the
exposure to light. This step converts the exposed silver halides to black
metallic silver, forming a visible image.
b. After the image appears, the emulsion is rinsed in stop bath to stop
further development of the halides.
c. Next, the film is placed in a fixing solution. The fixer converts
the unexposed, undeveloped silver halides into water-soluble salts. These
are removed in the fixer and the image is made permanent.