The papier-mache (literally, mashed paper) matrix was first
successfully used for casting stereotypes for book pages in France in
1848. Charles Craske, an engraver of New York, introduced the method
into the stereotype trade of the United States in 1850, and in 1854 he
stereotyped a page of the "_New York Herald_" and later made
stereotypes for other New York newspapers.
The modern wet stereotype "flong," in common use today, consists of
several layers of special paper pasted together to form a thick sheet.
The base is a sheet of special soft stock similar to firm
blotting-paper, such as is used between leaves of small blank books.
Three or four sheets of strong, white tissue are next added, each
sheet except the last being uniformly covered with the paste. The
pasting must be done with great care so as to cover the entire surface
of each sheet and at the same time to press out all air bubbles. The
sheets must then be pressed smoothly but not squeezed so hard as to
force the paste out and must be kept moist until used. In newspaper
syndicate plants, the "flong" is made automatically by a specially
devised machine into which the various kinds of paper used are fed
from rolls, the pasting and cutting into sheets being mechanical.
In molding a papier-mache matrix, the moist "flong" is laid on the
original molding form to be duplicated, the molding form being in
place on the table of the molding press. The "flong" is covered with
several blankets of thick felt and the table of the molding press is
then automatically moved in under a powerful roller which squeezes the
moist flong down into the form. At the end of its travel the table is
automatically brought back again under the rollers to the position
from which it started. The speed of the roller and the table is
synchronized to obviate any possibility of the mat becoming wrinkled
by sliding.
The molded matrix and the pattern with the blanket still on it is then
transferred to the drying press, in which under a hot platten it is
again squeezed and allowed to remain for a few minutes until the
moisture is completely expelled from the molded flong. The drying
press is kept at a high temperature, usually by steam heat.
The matrix thus dried out to a thick, flexible cardboard is then ready
for the casting of the stereotype, which is done by pouring molten
stereotype metal against the face of the matrix placed in a
casting-box designed for this purpose. A successive number of
stereotypes can be cast for the same mat before it is injured by the
hot metal. For job-work stereotyping the casting-box is flat, and the
molten metal is either poured by hand or automatically pumped in the
casting-box.
After the stereotype is cast it is flattened, rough shaved, smooth
shaved, bevelled or blocked on wood; the wood base trimmed and then
planed type-high for printing press use.
The large daily papers cast the full-page stereotype from which the
paper is printed in an automatic casting machine which forms a curved
plate, trimmed and bevelled, to fit the cylinder of the press.
Stereotyping was for many years the chief means of making plates for
books and also for commercial printing. It has several advantages. The
first, obviously, is the advantage which it shares with several other
methods of providing a solid printing plate made by molding from an
original form of type or engraving. Its peculiar advantage, however,
is that it is the quickest method of producing a duplicate plate from
an original.
In comparison with electrotyping, however, it has two distinct
disadvantages. One is that it is not adapted for reproducing the fine
lines of engravings and type faces. In addition it is comparatively
shallow and does not possess a sharp, clean printing face. The other
disadvantage is that a stereotype is relatively soft and quickly worn.
Stereotypes have been made more durable, to withstand the wear of
printing, by the deposition of a film of harder metal--copper or
nickel--on the face of the plate after it has been cast. This,
however, is not satisfactory, as it involves not only another
operation, but also makes an already shallow printing plate that much
shallower and increases the probability of it printing "dirty," which
is one of the chief objections to the stereotype in itself. This
practice is not recommended.