IMPROVEMENTS IN THE PROCESS OF ENGRAVING ON METAL PLATES IN RELIEF
Year: 1873

page_text: LETTERS PATENT to George Moore, Artist, and Benjamin Constant
Le Moussu, Civil Engineer, both of Haverstock Hill, in the County
of Middlesex, for the Invention of "IMPROVEMENTS IN THE PROCESS OF
ENGRAVING ON METAL PLATES IN RELIEF.”
PROVISIONAL SPECIFICATION left by the said George Moore and
Benjamin Constant Le Moussu at the Office of the Commissioners
of Patents, with their Petition, on the 18th July 1873.
We, GEORGE MOORE, Artist, and BENJAMIN CONSTANT LE MOUSSU,
Civil Engineer, both of Haverstock Hill, in the County of Middlesex,
IMPROVEMENTS
do hereby declare the nature of the said Invention for "
IN THE PROCESS OF ENGRAVING ON METAL PLATES IN RELIEF," to be as
follows:-
Our Invention has reference to the production of a substitute for
mood onemazing and consists in hollowing out to the required depth by

page_text: means of acid those portions of the plate which have hitherto required
to be so cut and deepened by the use of a graver or cutting instrument.
For this purpose a drawing is made on the plate by the ordinary process
of etching, and after biting in with acid to a slight degree, another
metal capable of resisting acid is fused on to the plate so as to produce
a drawing in relief; then the parts in relief are rolled in and thereby
covered with a varnish capable of resisting acid. We prefer to use for
this purpose a varnish composed of lithographic transfer ink and resin.
When the raised parts are thus protected a further process of biting with
acid (with or without the aid of electricity) is applied to the sunken
parts, which process may be repeated as often as required to deepen such
parts sufficiently to adapt the plates for printing in the manner in which
engraved wooden blocks are ordinarily employed.
SPECIFICATION.in pursuance of the conditions of the Letters Patent,
filed by the said George Moore and Benjamin Constant Le
Moussu in the Great Seal Patent Office on the 17th January
1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, GEORGE
MOORE, Artist, and BENJAMIN CONSTANT LE Moussu, Civil Engineer,
both of Haverstock Hill, in the County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighteenth day of July, in the
year of our Lord One thousand eight hundred and seventy-three, in the
thirty-seventh year of Her reign, did, for Herself, Her heirs and suc-
'cessors, give and grant unto us, the said 'George Moore and Benjamin
Constant Le Moussu, Her special license that we, the said
George Moore and Benjamin Constant Le Moussu, our executors,
administrators, and assigns, or such others as we, the said George:
Moore and Benjamin Constant Le Moussu, our executors, admini-
strators, and assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN

page_text: THE PROCESS OF ENGRAVING ON METAL PLATES IN RELIEF," upon the condition
(amongst others) that we, the said George Moore and Benjamin
Constant Le Moussu, our executors or administrators, by an instrument
in writing under our, or their, or one of their hands and seals, should
particularly describe and ascertain the nature of the said Invention,
and in what manner the same was to be performed, and cause the same
to be filed in the Great Seal Patent Office within six calendar months
THE PROCESS OF ENGRAVING ON METAL PLATES IN RELIEF," upon the condition
(amongst others) that we, the said George Moore and Benjamin
Constant Le Moussu, our executors or administrators, by an instrument
in writing under our, or their, or one of their hands and seals, should
particularly describe and ascertain the nature of the said Invention,
and in what manner the same was to be performed, and cause the same
to be filed in the Great Seal Patent Office within six calendar months
next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that we, the said George Moore and Benjamin
Constant Le Moussu, do hereby declare the nature of our said Inven-
tion, and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement (that is
to say):
Our Invention of "Improvements in the Process of Engraving on
Metal Plates in Relief" has reference to the production of a substitute
for wood engraving, and consists in hollowing out to the required depth
by means of acids those portions of the plate which have hitherto
required to be so cut and deepened by the use of a graver or cutting
instrument. For this purpose the plate is covered with an ordinary
etching ground, and a drawing is made by means of an etching needle
in the ordinary manner of producing etchings on copper. After the
drawing is thus made the plate is put into a bath of acid so as to bite in
the drawing to a slight degree. The etching ground is then cleaned off
from the plate, which is made as clean as possible, and the plate is
warmed, and a metal composed of bismuth, lead, and tin, or other metal
or alloy of metal capable of resisting acid is fused on to the plate so as
to pass into and fill up those parts of the plate which have been bitten
in and form the drawing. The result of this process is a plate with a
smooth surface susceptible of being acted upon by acid, and with a
drawing or etching inlaid with another metal which is capable of resist-
ing the action of acid. The plate is again put into the bath of acid,
which bites or eats away the metal liable to the action of acid, thereby
leaving in relief the design or parts covered by the metal not liable to
the same. After preparing the plate so far the practice hitherto
employed has been to take a cast of the plate in a softer metal and
clear away by hand the large spaces which are not deep enough for the
plate to be printed from.

page_text: Now our Invention consists in deepening such spaces in the first plate
to a sufficient extent to print from without requiring a cast to be taken
of the drawing. in relief, or to clear away the intervening spaces by
hand. And this effect is produced in the manner and by the means
herein-after described...
When the drawing is raised slightly in relief we take a printer's roller
covered with a varnish of lithographic transfer ink, or other suitable
varnish, and roll in the plate so as to cover the surface of the design
therewith, we then dust over this varnish with powdered resin which
adheres to the varnish. We then warm the plate slightly, and thereby
melt the resin, which causes the varnish to run down each side of the
drawing or parts in relief. The object of this is to prevent the acid from
biting under the drawing. The design in relief is thus protected from
the action of acid at the top by a metal capable of resisting such action,
and at the sides by the varnish. Then while the plate is warm we plunge
it into cold water by which the varnish is made hard. The plate is then
again put into the bath of acid, which bites away the unprotected parts
of the plate a little more, and leaves the drawing more in relief. The
plate is afterwards removed from the bath, and the several processes of
rolling in with varnish, applying resin, warming the plate to melt the
varnish, cooling it to harden the same, and biting in with acid, are
repeated until the hollows are deepened to the extent required for the
plate to be printed from. If preferred, the above described process of
warming the plate may be dispensed with by using the varnish in a more
liquid state. By the means above described the finer lines of a drawing
may be preserved owing to their being protected by the metal capable of
resisting the action of acid.
I
Having thus described the nature of the said Invention, and in what
manner the same is to be performed, we hereby declare that we do not
claim as of our Invention any of the processes or parts of processes
herein-before described otherwise than as preparatory for the final result
of sufficiently deepening the hollow parts of the plate to admit of its
being printed from, neither do we claim the process of deepening the
hollow parts by means of acid, except when the drawing is protected by
a metal capable of resisting the action of acid, but what we do claim as
of our Invention is, the production of engravings in relief on plates of
metal inlaid with a suitable metal by sufficiently deepening the hollow
parts of a design by means of acid in the manner described, so as to

page_text: dispense with the need of taking casts from the original plate and of
deepening the said hollow parts by hand.
In witness whereof, we, the said George Moore and Benjamin
Constant Le Moussu, have hereunto set our hands and scals,
this Seventeenth day of January in the year of our Lord One
thousand eight hundred and seventy-four.
Witness,
BENJAMIN CONSTANT LE MOUSSU. (L.S.)
WILLIAM SPENCE,
8, Quality Court,
Chancery Lanc.