A MODE OF PREPARING OR FACING THE SURFACES OF ENGRAVED OR ETCHED PLATES OF METAL OR OTHER SUBSTANCE, SO THAT THEY MAY BE READILY PRINTED FROM BY A PRESS WITHOUT WIPING
Year: 1856

page_text: application for Letters Patent was not given within the time prescribed
by the Act.)
PROVISIONAL SPECIFICATION left by Theodore Bergner at the Office of
the Commissioners of Patents, with his Petition, on the 7th February
1856. A communication from Samuel W. Lowe, of Philadelphia.
I, THEODORE BERGNER, of Philadelphia, in the United States of America,
and of No. 19, Arundel Street, Strand, in the County of Middlesex, having a
communication from Samuel W. Lowe, of Philadelphia, do hereby declare the
nature of the said Invention for A NEW MODE OF PREPARING OR FACING THE
SURFACES OF ENGRAVED OR ETCHED PLATES OF METAL OR OTHER SUBSTANCE, SO
THAT THEY MAY BE READILY PRINTED FROM BY A PRESS WITHOUT WIPING, to be
as follows:-
The nature of the Invention consists in coating or amalgamating with
mercury the unengraved parts of the surface of any engraved or etched plate
of metal, or other substance, capable of receiving or being made to receive or
amalgamate on the surface with mercury, so that the said engraved or etched
plate may be continuously printed from by a letter-press, or any other suitable
form of press, either alone or in the same form with the type, and without
wiping" the surface of the plate, as heretofore required in the process of
printing from copper or steel-plates.
In preparing an engraved or etched steel plate for the purpose, I first per- .
fectly fill up all the engraved or etched figures on the plates with any suitable

page_text: gum, resin, wax, or composition, so. as to finally leave the plain or unengraved
surface bare; then, by the galvanic process (which is well understood and
therefore need not be described). I coat the plain or unengraved surface with
copper, sufficiently thick to receive and amalgamate with mercury, by rubbing
it on the surface of the same, so as to fix a thin mercurialized surface upon the
plate. The gum, wax, or other filling may now be removed, and the plate is
ready for the press.
In preparing an engraved or etched copper-plate for the purpose, there
being sufficient affinity between the copper surface of the plate and the
mercury, the
galvanizing process is not required; but in all other respects
the engraved plate is prepared precisely as the steel one, as just described;
the object in both cases being to coat the.unengraved surfaces of the plates
with a mercurial amalgamı, as I have discovered that when so coated, the ink
used in printing, when applied with a "sharp inking roller" (which is the
term usually given by the printers to the common elastic inking roller when it
is in the best condition for use in.inking type); will not adhere to, nor, even: soil,
the mercurialized surface of the plate, whilst it fills and remains in the engraved
lines thereof, and therefore the plates thus prepared can be continuously printed
from by letter-press, "wiping" of course not being required. It will now be
readily perceived, that by this discovery common tin plate can be used in
place of copper or steel-plates for the purpose of receiving engraved or etched
figures, and be printed from continuously by letter-press, either alone or in the
same form with the type, as just described. In preparing the tin plate for the
purpose, first coat it over, with the usual etching ground. (which process.is
well understood and need not be described); and with the common engraving
instruments or points produce the figures required in the usual manner. I
then apply nitro-muriatic acid, or any other suitable acid; which.acts upontand
dissolves away, the exposed tin coating; after which the acid is washed off, and
the etching ground removed. I then rub on the mercury, as before:described,
until a thin mercurialized surface is formed by amalgamation upon the: plain
or unetched surface of the, plate, and it is ready for the press; the etched figure
being bitten through the tin to the iron, plate, beneath,t.and the mercury+not
having an affinity for the iron, no part of the plate becoines mercurialized
but the plain unetched surface, and consequently, for the reason already given,
the plate may be readily used to print from continuously by a letter-pressor
any other suitable form of press, either alone, or in the same form with the
type, as before described, "wiping" not being necessary, or required..
:
It will also be apparent that the tin plate may be simply engraved, through
to the iron with a graver instead of etching, and that the unengraved surface

page_text: may be mercurialized and used precisely: in the same manner, and that any
cheap material whatever, which may be capable of receiving or being made to
receive a thin mercurial; coating or amalgámesurface, can be thus used as a
substitute for the: more; expensive and costly steel or copper-plates as here-
tofore, required; and although a copper-plate press may be used in printing
from, the plates, as prepared by my process, the common letter-press or any
kind of press suitable to the form and material of the plates can be used, so
that for almost all kinds of illustrations for books, cards, &c. my discovery or
Invention is admirable adapted, as the engraved plate thus prepared *can be
rapidly printed. from by, a letter or other press; whether operated by hand or
machine power, in the same form with the type; and without."wiping" the
surface of the plate..
1
The coating produced by amalgamating or mercurializing the tin plates; as
described; I have found to be more fixed and durable than the coating pro-
duced by amalgamating with mercury alone the surfaces of tlie copper-platės;
and as this difference arises from a greater tenacity in an amalgam composed
of tin and mercury, it is found that by amalgamating as much tin with the
mercury as it will bear without losing a semi-fluid condition produces a better
material for coating the surfaces of copper-plates, because the surfaces are
thereby rendered more tenacious and durable, without impairing in the least
the peculiar quality which the mercurial coating possesses of resisting the ink,
as before described.
In preparing steel plates for being printed from, by mercurializing their
surfaces, as described, another mode may be adopted, which I have used with
perfect success, as follows:-I take a weak solution of sal ammoniac (muri-
ammonia) in water, and rub it over the clean surface of the engraved steel-
plate (after the engravings are filled with such resinous substances as before
described), and then apply the mercury, by continuing the rubbing with the
finger, or with a little raw cotton, or a rag, until the steel surface becomes
coated with the mercury (which will be in a few moments); I then apply a
sheet of tin foil, pressing it down with the fingers in smooth and even contact
with the mercurial surface, and let it so remain undisturbed for about an hour,
at the expiration of which time it will become perfectly fixed; I then rub the
surface over with mercury in the same manner as directed for the tin plates,
and the steel plate is ready for the press.
I alopt the same mode for mending the tin plates, in case a mistake is
made in any part of the engraving or etching, or in case of damage done to
the surfaces thereof from any cause.
The plates thus prepared, whether of steel, copper or tin, are designed to be

page_text: printed from by means of an ordinary type printing press, or any press acting
by direct pressure, whereby it is made possible to print at the same time and
on the same press with the type or letters, any illustrations and embellishments
executed in the style of steel or copper-plate engravings, in place of wood
engravings; yet as these plates are adapted also for printing from or for
embossing by means of a copper or steel plate roller press, the addition of tin
to the mercury for the purpose of producing a more tenacious and durable
alloy upon the surfaces of the plates becomes the more important and
advantageous.
In printing from the engraved copper, and also from the engraved steel
plates, prepared according to either of the processes described, it is not neces-
sary to remove the resinous substance from the engraved lines after the
surfaces of the plates are mercurialized or coated with the amalgam of tin
and mercury, or, rather, it is best to leave them filled with the resinous sub-
stance, because such substance, while it readily takes the ink from the roller,
also yields it as readily to the paper under the moderate pressure of a common
type printing press.