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
19th September 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. If there are several colors, I prick or bite each color, and transfer
them 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 then varnish them with engraver's varnish, or I ink them
by means of a roller with lithographic ink thickened by tallow and wax to
preserve all the parts which are to remain in relief. I take an impression on

page_text: 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 by the acid
or pile, which is continued until the engraving is effected.
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
autographic or lithographic ink, and after the ordinary lithographic pre-
parations 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, transformed 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, openwork 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
1
-
-
5 parts.
5
"
- 2
"
"
- 2
"
- 2
"
These substances are ground and mixed into a paste, and I spread the com-
position in regular layers on a metal plate, and apply thereon by pressure 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 scoured metal plate or roller,
and pressure effects the transfer, as in lithography. I blacken by means of
a lithographic roller, and then place the metal plate or roller in a bath
prepared of

page_text: I produce galvanic action, the design disappears in the bath, and is
engraved in intaglio. The metal plate or roller being thus engraved, I re-
produce 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
Honey
5 parts.
10
Gum
Garlic
"
5
"
2
"
- 10
وو
Ordinary black
Red chalk (sanguine) in suitable quantity.
The whole is well pounded and mixed to a paste. I take an impression
and transfer it to a prepared stone. I cover it with mineral powder, and I
ink the stone by a roller with lithographic black. I fix and prepare the stone
in the ordinary manner, and the design appears in white, that is to say, a
negative. I take an impression from it, and transfer the impression to metal
in the manner previously described for producing an engraving in intaglio.
Fifth, reproduction of old engravings.-I obtain a design or an old engraving
on stone or metal by known processes of photograpy and heliography, which I
apply to printing on stuffs by the known means of bichromate of potass, or
Judea bitumen prepared in darkness with water and gum. I leave it to dry,
and I apply the design on stone or metal. I expose it to light, as in photo-
graphy, after the operation in the dark chamber. I powder it 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 in "marseilles" or other soap water; the fatty body does not

page_text: 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.