IMPROVEMENTS IN ENGRAVING ON METAL
Year: 1865

page_text: PROVISIONAL SPECIFICATION left by Richard Archibald Brooman at
the Office of the Commissioners of Patents, with his Petition, on the
22nd March 1865.-A communication from abroad by Narcisse Guilbot
and Pierre Heritier, both of Paris, France.
I, RICHARD ARCHIBALD BROOMAN, of 166, Fleet Street, in the City of
London, Patent Agent, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN ENGRAVING ON METAL," to be as follows:-
This Invention consists of new processes of engraving in intaglio and in
relief on metal plates and rollers by photography, lithography, and by biting
in an electric bath, or by aquafortis, for printing on stuffs, paper, leather, and
other substances.
To produce on metal plates or rollers (copper, steel, or zinc) engravings in
intaglio or in relief of objects photographed or drawn by hand in one or several
colors for printing on fabrics, leather, and other substances I employ the
following processes :-
First. Engraving in Relief.-I draw by hand, or produce by photography, of
any convenient dimensions, flowers, fruits, animals, and other objects or designs.

page_text: If there are several colors I prick or bite each color, and transfer to as many
stones as there are colors, which I separate by marks. I then strike off
impressions on paper, I transfer these impressions to metal by lithography;
I varnish with engravers' varnish; or I ink by means of a roller with litho-
graphic ink thickened by tallow and wax to preserve all the parts which
are to remain in relief. I take an impression on metal with Judea powder or
resin, and I place the plate in a nitric acid bath of from 15° to 20° Beaumé ;
or I submit it to the action of a galvanic pile. After a biting of about
20 minutes, I heat the plate or I ink it again to protect the feeble parts, and
I recommence the operation of biting
until the engraving is effected.
the acid or pile, which is continued
Second. Engraving in Intaglio.-To engrave in intaglio I draw on stone with
an ink composed of gum, China ink and acid, I cover the stone with auto-
graphic or lithographic ink, and after the ordinary lithographic preparations I
obtain a design in white, that is to say, a negative, which I transfer to metal,
and the engraving of which in intaglio by biting, or by a galvanic pile is effected
in the manner before described. A design may be changed from black to white
by striking off an impression on paper, the design is covered with pulverized
gum arabic transferred to stone covered with lithographic ink, and washed,
and the change from black to white thereby effected.
Third. Engraving in Intaglio by reserve of Lace Open-work Designs and
others. To reproduce lace, guipure, embroidery, and designs on stuffs, textile
fabrics, paper, and other substances I proceed as follows:-To obtain by
reserve an engraving in intaglio on metal of a piece of lace, or of an open-
work design, I transfer the design directly or indirectly by photography,
lithography, or otherwise, I then cover the metal plate with the following
composition :-
Gum arabic -
Narbonne honey
Natural garlic (essence)
Distilled water
Fine starch
Albumen
-
5 parts.
5
"
2 parts.
5 parts.
2
99
2
"
These substances are ground and mixed into a paste, and I spread the
composition in regular layers on a metal plate, and apply thereon by pres-
sure the piece of lace or other design in order that it may imbibe or take up
some of the composition. I then remove the lace to a second metal plate or
roller, and pressure effects the transfer as in lithography. I blacken by means

page_text: of a lithographic roller, and then place the metal plate or roller in a bath
prepared of
Rain water
Nitric acid
Sulphuric acid
Alcohol -
-
100 quarts.
1 quart.
"
"
I produce galvanic action, the design disappears in the bath," and is
engraved in intaglio. The metal plate or roller being thus engraved, I repro-
duce or produce copies of the lace or other design on textile fabrics, paper,
and other substances by a hand plate or roller. By this process of engraving
I print in all colors by reserving the design on all the grounds, thus, for
example, I obtain on a white ground white lace in reserve. With other
plates I obtain junctions in all colors in the ground of lace and guipure, and
I print the lace without a reverse or wrong side by counter impression. By
these processes I obtain the reproduction or impression in well dyed fixed
and washed colors of lace, and all designs applied to printing on fabrics and
paper with reserves and junction.
Fourth. Negative Impression.-To obtain an engraving in intaglio on metal
I draw on a lithographic stone with pencil or pen in lithographic ink the
design the engraving of which is to be obtained. I ink the stone by means
of a roller with the following composition :-
China ink
5 parts.

page_text: graphy. After the operation in the dark chamber I powder with gold, or plunge it
in lithographic ink, the soluble parts only take the powder or ink, and the desired
reproduction of the design is thus obtained. I also obtain a negative design
by plunging a metal in nitric acid. I transfer to metal by lithographic printing
the design which has been dipped in a bath of nitrate of silver of 20 per cent.
with distilled water; I powder the plate with gold, or plunge it into Marseilles
or other soap water, the fatty body does not become attached to the nitrate, it
is only the negative which receives it by this method. I can ink and take
impressions which I transfer to metal to be engraved.
I also obtain designs by preparing sensitized collodion in darkness; I apply
the design to metal, and proceed as before.