The ferrotype and how to make it - The Grian Press

118 THE FERROTYPE.
to dry and varnish the holder with naphtha var-
nish.
Fogs from the admission of light into the
camera box, the holder, or the dark room, are
not the same in appearance as fog from the bath,
being of a lighter color, and being apparently in
the substance of the film, while that from the
bath appears to lie upon the surface, and can
frequently be removed with a piece of cotton or
a soft brush.
Fogs are caused sometimes by the developer,
more often in hot weather than otherwise, and by
foreign substances getting into the developer.
To ascertain the cause of fog, first see that
your camera-box and plate-holder are tight, and
that the dark room admits no light ;
then change
your developer, cleaning the bottle carefully, and
if the weather is hot, cool the developer ; next test
the bath, and if neutral, add a drop or two of acid.
On trying a plate, you will probably find that the
fog has disap})eared.
Transparent spots, or as they appear on the
ferro-plate, black spots, are produced by particles
of dust adhering to the surface of the plate.
Very often, brushing the plate to remove dust
from the surface, produces an electrical condition,
which causes it to attract and hold small particles
of varnish, which chip off the edges, and parti-
cles of dust also adhere to the lip of the Collo-
dion bottle, and upon coating the plate they
become incorporated with the film, and produce