The ferrotype and how to make it - The Grian Press

88 THE fi:rrotype.
distilled with suli)hurie acid, which removes the
soda, and liberates acetic acid, which, being vola-
tile, distills over and may be condensed.
The use of acetic acid in the developing so-
lution, besides its preservative effect upon the
solution itself, is for the purpose of retarding the
action of the iron in the reduction of the salts of
silver to a metallic state, also favorably affecting
the character of the deposit. Alcohol is used in
the developing solution for the purpose of caus-
ing it to flow evenly and smoothly over the sur-
face of the plate.
When new silver is used for coating the plate,
the developer requires no alcohol, but as every
plate which is immersed in the silver solution im-
parts to it a portion of ether and alcohol from
the collodion film, the silver bath soon acquires
enough to change somewhat the character of the
sensitized surface, giving it the power to repel
the developing solution. By the addition of
alcohol to the developing solution this repelling
power is overcome.
We will now describe the process of develop-
ment. The correct definition of the last word of
the title at the head of this article, according to
Webster, is, '^ The act of developing or disclosing
that which is unknown," and beautifully describes
one of the wonderful processes of our art.
A ferro-plate is coated with collodion and immersed
in a solution of nitrate of silver. After
being allowed to remain a few minutes, it is re-