Section V. OPERATION UNDER UNUSUAL CONDITIONS
32. Arctic Areas
Projector PH-637(*)/PFP is not designed for operation at low
temperatures. When the equipment has been stored outdoors or in
an unheated shelter where extreme temperatures are encountered,
proceed as follows before operating it.
a. Move the equipment into the room in which it is to be operated,
and let it remain at room temperature for approximately 6 hours
before removing the protective covering. If the cover is removed
sooner, water may condense on the equipment and cause permanent
damage. Whenever possible, inclose the covered equipment in water-
repellent material before transferring it from the cold storage area
to room temperature. The water-repellent material over the protec-
tive covering should decrease the possibility of water condensing on
the equipment.
b. Before operating the equipment, clean and dry the glass window
on the projection head and the plate glass cover of the projection
stage. Then turn the projection lamp and blower on for 10 or 15
minutes to evaporate any remaining moisture.
33. Cold-Weather Processing
Note. The information contained in this paragraph is for use only by qualified.
photographic laboratory personnel.
a. General Information.
(1) In processing sensitized materials, use the standard, pack-
aged, Signal Corps specification formulas whenever they
are available.
(2) Freezing does not affect the action of processing solutions
if they are warmed until the chemicals have redissolved.
Jugs of processing solutions should not be tilled to more than
80 percent of capacity, because they may crack under pressure
when the solutions freeze. Air near the ceiling of a room
is usually warmer than air near the floor; therefore, storing
processing solutions near the ceiling will help to prevent
them from freezing.
(3) Many photographic solutions are prepared in concentrated
form to save space and to speed up processing. Most solu-
tions will not be saturated above 40 F. When the temper-
ature falls a few degrees below 40 F., however, marked
precipitation usually takes place. Chemicals precipitated
out of solutions are inactive, weaken the solutions, and are a
nuisance because suspended or floating crystals cause specks
or spots on sensitized materials. I f t h e p r e c i p i t a t e i s r e -
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