rinse bath is commonly used between development and
fixation to slow down the development by removing all
the developer that is clinging to the film (or paper)
surface. A rinse bath does not completely stop
development but retards it. A rinse bath has little affect
on the developer that is actually in the swollen emulsion.
changed often to ensure it does not become loaded with
developer. It is better to use running water.
work that has to be done by the acid in the fixer. Rinsing,
therefore, protects or prolongs the useful life of the fixer.
bath to stop the development.
to use an acid stop bath. The function of a stop bath is
not only to remove the developer that is clinging to the
surface of the material but to also neutralize the
developer in the swollen emulsion to stop development
the life of the fixer by neutralizing developer carry-over.
free-acid content of the fixing bath and cause
the fixing bath have a tendency to form carbon dioxide
the developer and placed directly into a strong acid or
fixing bath, these bubbles may break and cause small,
round holes in the emulsion. These bubbles are
sometimes mistaken for pinholes like those caused by
dust particles settling on the emulsion before camera
materials pass through it. Therefore, you cannot use a
strong acid (such as sulfuric acid) because it can cause
precipitation of sulphur in the fixer. Acetic acid is the
type of acid used for stop baths. In its pure form as
glacial acetic acid (99.5 percent), it freezes at a
temperature of about 61°F. Its freezing tendency gives
it the name "glacial." For use as a stop bath, 99.5 percent
glacial acetic acid is diluted with water to make a 28
percent working solution. Approximately 1/2 ounce of
of water. The process of determining the concentration
amount of silver salts (halides) that has not been affected
(developed) by the developing agents. This silver salt is
still sensitive to light, and if it remains in the emulsion,
light ultimately darkens and discolors the salt which
obscures the image. Obviously, when this action occurs,
the negative (or print) is useless.
accomplishes this by removing the undeveloped silver
halides by making them water soluble. Therefore, to
make an image permanent, you must "fix" the
light-sensitive material by removing all of the
unaffected silver salt from the emulsion.
hardening agent, and an antisludge agent.
sodium and ammonium thiosulfate, commonly termed
hypo (taken from their other chemical name
hyposulfite). Ammonium thiosulfate is used in rapid
Basic Photography Course