LESSON 1
This procedure will produce a more uniform and thorough fixation, conserve
chemicals, and speed up the production.
(b) Standard practices in fixation must be followed closely since
there are dangers in both overfixing and underfixing.
Inadequate fixing
often produces stains on prints. Overfixation tends to produce a thinning
or weakening of the photographic image.
(c) Agitation prevents exhausted hypo from settling near the
surface of the emulsion which would prevent quick and effective entry of the
thiosulfate into the gelatin of the emulsion.
Of the projected time
required for complete fixing, the greatest proportion involves the entry and
spread of the chemical into the emulsion. Accordingly, it is important to
agitate the solution to speed up the process of chemical diffusion. Do not
permit prints to overlap each other in the fixer for more than a few
seconds, otherwise unequal fixing may occur.
(8) An optional tray full of water may be used as a holding tank
until you have produced enough prints to make it worth your while to use a
proper wash tank.
3.
Washing and drying paper.
a. Washing the paper is normally done in an automatic print washer.
This washer rotates the prints in rapidly changing water at 65 to 70 degrees
F.
b. The washing time is determined by the type, size, weight, and
quantity of prints to be washed; also if a hypo clearing agent was used.
(1) Smaller size prints (4x5 and 5x7) are separated more easily and
therefore wash faster.
Larger prints (8x10 and 11x14) stick together and
need longer washing.
(2) Single weight papers need half the wash time as double weight
papers.
(3) The quantity of prints washed will determine if increased wash
time is needed. For example, 20 8x10 prints will wash faster than 100 8x10
prints.
(4) RC papers only require
4
minutes
to
wash,
while fiber-based
papers generally need 45 minutes.
c. If you use, and it is highly recommended, hypo clearing agent
according to instructions, you can reduce the washing time.
The new wash
time will be 10 minutes for single weight and 20 minutes for double weight
prints. As you can see, there
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