“The collodion being dry, the plates are coated with emulsion. The
emulsion flows very badly on the collodionised surface, but by using a
bow made of a piece of sewing cotton stretched across an arc of thin
iron wire the difficulty may be readily overcome. The thread is to
be drawn over the surface of the plate after the required quantity of
emulsion has been poured on, and it is scarcely necessary to say that
the glass should be supported on a levelling stand.
“Plates prepared in this way are developed and fixed in the ordinary
manner, and when a plate is dry it is sufficient to cut through the
film inside the edge which has been cleaned of wax, when the film
negative can be easily stripped off. In this case, however, the film
is very thin, and it is often desirable to thicken it somewhat before
stripping. For this purpose a piece of thin commercial sheet gelatine
is taken, and soaked in water till it becomes quite flaccid, and this
is laid on the negative, care being taken that no air is enclosed
between them. A sheet of wet paper, or of mackintosh, is now laid on
the gelatine film, and all excess of water expelled from between the
negative and the soft gelatine film by stroking the upper surface of
the paper, or of the mackintosh cloth, with a squeegee—that is to say,
with a strip of indiarubber set in a wooden handle.
“It is now easy to remove the paper or the indiarubber cloth which was
used to protect the soft gelatine from the action of the squeegee,
and the plate can be set up to dry. When dry, the film is cut through
within the border from which the wax was cleared off, and the film will
separate readily; but should there be any tendency towards a too early
separation, owing to the contractile force of the fresh thickness of
gelatine, the edges of the plate may be bound with strips of gummed
paper.” (_Photographic News._)
Public-domain text, read in full here on John Shaqi.
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