EXERCISE
2.
If a formula calls for sodium carbonate desiccated, and all you have in stock is sodium carbonate
monohydrated, you would (select one):
a. use the same amount.
b. increase the amount by 17%.
c. wait until you have the chemical called for before mixing the solution.
d. decrease the amount by 17%.
1-3.
WATER PURIFICATION TECHNIQUE
Water used in photography should be as pure as possible for best photographic quality.
(1) Boiling water causes the mineral, vegetable, and animal matter in the water to coagulate.
When the water is allowed to coal and stand, the impurities will settle to the bottom and clean water on
the top can be poured off.
(2) Chemical precipitation. By adding certain chemicals to the water you can cause the
impurities to coagulate or precipitate and settle to the bottom.
(3) Distillation requires a "still," whereby water is changed to steam, separating it from its
impurities.
(4) Filtration means to pass water through a fine mesh cloth or cotton.
(15) Water used in photography should
be as pure as possible for best
photographic quality.
For best results in photography,
you should use water that is as
___ _ _ _ _ _ _ _ _ _ _ _ _ _ as possible.
pure
(16) Boiling water causes the mineral,
vegetable, and animal matter in the
water to coagulate. When the water
is allowed to cool and stand, the
impurities will settle to the bottom
and the clean water on top can be
poured off.
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