The first and indispensable operation, in the preparation of the surface
to receive the transfer, is the "sizing of the surface." It simply
consists of a solution of gelatine chrome-alumed, as follows:
Gelatine. 10 grains.
Water. 1 ounce.
A trace of chrome alum.
Coat with a soft camel's hair brush and let dry. It is needless to say
that numbers of _plaques_, plates, vases, etc., may be coated right off,
and will then be ready for use at any time.
Having settled on the subject and carefully dusted the negative, as well
as placed it _in situ_ for reproduction, the next thing required is a
suitable collodion, and the following will be found all that can be
desired: