IMPROVEMENTS IN ENGRAVING, BOTH SUNK AND IN RELIEF, ON METAL, STONE, AND OTHER HARD SUR- FACES
Year: 1877

page_text: LETTERS PATENT to Désiré L'heureux and Hippolyte Ligny, both of Copen-
hagen Street, in the County of Middlesex, and Percy Cocker, of Hampstead
Road, in the same County, for the Invention of "IMPROVEMENTS IN ENGRAVING,
BOTH SUNK AND IN RELIEF, ON METAL, STONE, AND OTHER HARD SUR-
FACES"
Sealed the 5th March 1878, and dated the 7th September 1877.
PROVISIONAL SPECIFICATION left by the said -Désiré L'heureux, Hippolyte
Ligny, and Percy Cocker at the Office of the Commissioners of Patents on the
7th September 1877.
DÉSIRÉ L'HEUREUX and HIPPOLYTE LIGNY, both of Copenhagen Street, in the
County of Middlesex, and PERCY COCKER, of Hampstead Road, in the same County.
"IMPROVEMENTS IN ENGRAVING, BOTH SUNK AND IN RELIEF, ON METAL, STONE, AND
OTHER HARD SURFACES."
The object of the present Invention is to engrave both sunk and in relief (as may
be required) on metal, stone, or other hard surfaces with greater facility than
heretofore.
To this end the design which it is intended to engrave on the metal or other
hard surface is drawn either on the surface itself or on paper, from which it is trans-
ferred to the hard surface by pressure. The design must be drawn with a specially
prepared ink, composed of some substance which is capable of crystallizing or
becoming hard when deprived of its moisture by drying, but which may be easily
dissolved and washed away by means of water. The substances which we prefer to
employ for this purpose are either sugar, gum arabic, silicate of potash or soda, or
other soluble salt.
A strong solution of these substances, or either of them, in water is made, and any
soluble inert coloring matter which will not chemically affect the crystallizable sub-
stance or reduce its solubility is added to the solution for the purpose of giving a
colour to it, so that the artist can use it like ordinary ink.

page_text: We find it convenient, before transferring the design from the paper to the plate,
to cover the latter with a thin film of ammonia by pouring some liquid ammonia on
the surface and allowing it to dry thereon, when heat is applied to the under
surface of the plate. The design is then to be transferred from the paper to the
plate by placing the paper design face downwards on the plate, and subjecting it to
pressure.
Upon carefully removing the paper the design will be found to be transferred to
the plate, the surface of which is then covered with a ground made of pitch dis-
solved in some suitable solvent, or pitch mixed with virgin wax; this will completely
cover up the design or picture, but upon pouring hot water on to the plate from the
height of a few feet, the wax or pitch ground will be softened, and the soluble
crystalline ink of the design or picture will swell up and burst through the thin
film of pitch or other ground, and will be very quickly dissolved and washed away
by the hot water. When this has been effected the pitch or wax ground may be
hardened again by the application of cold water to the surface of the plate. The
design may then be bitten in by means of acid, as in the ordinary operation of
etching on steel or copper plates.
When the drawn pattern contains very fine lines it will sometimes become
necessary to give a little substance to the lines before laying on the pitch or wax
ground; this is effected by dusting over the surface of the plate finely pulverized
soda or other soluble salt, which will adhere to the crystalline ink of the design
provided it be not quite dry and hard. By this means the lines of the design may
be deepened and thickened. The ground may then be put on the surface, and the
process carried on in the manner just explained.
It is scarcely necessary to say that if the design to be produced on the plate is to
be in relief, such parts as are to be in relief must be drawn in in ink which will not
be acted upon either by water or by the acid used for biting in.
The process for removing any soluble substance from the surface so as to leave
those parts of the surface which are covered therewith exposed to the action of the
acid in "biting in" is the same as when the design is sunk, as in ordinary
engraving.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Désiré L'heureux, Hippolyte Ligny, and Percy Cocker in the Great
Seal Patent Office on the 7th March 1878.
DÉSIRÉ L'HEUREUX and HIPPOLYTE LIGNY, both of Copenhagen Street, in the
County of Middlesex, and PERCY COCKER, of Hampstead Road, in the same County.
"IMPROVEMENTS IN ENGRAVING, BOTH SUNK AND IN RELIEF, ON METAL, STONE, AND
OTHER HARD SURFACES."
The object of the present Invention is to engrave both sunk and in relief (as may
be required) on metal, stone, or other hard surfaces with greater facility than
heretofore.
To this end the design which it is intended to engrave on the metal or other
hard surface is drawn either on the surface itself, or on paper, or on some film or
fabric, from which it is transferred to the hard substance by pressure.
The design
must be drawn with a specially prepared ink, composed of some substance which is
capable of crystallizing or becoming hard when deprived of its moisture by drying,
but which may be easily dissolved and washed away by means of water. The sub-
stances which we prefer to employ for this purpose are either sugar, gum arabic,
silicate of potash or soda, or other soluble salt.
A strong solution of these substances, or either of them, in water is made, and
any soluble inert coloring matter which will not chemically affect the crystallizable
substance or reduce its solubility is added to the solution for the purpose of giving
a color to it, so that the artist can use it like ordinary ink.
We find it convenient, before transferring the design from the paper to the plate,
to cover the surface of the latter with a thin film of ammonia by pouring some
liquid ammonia on the surface and allowing it to dry thereon, when heat is applied
to the under surface of the plate. The design is then to be transferred from the
paper or other fabric to the plate by placing the paper design face downwards on
the plate, and subjecting it to pressure.
Upon carefully removing the paper or other film or fabric the design will be
found to be transferred to the plate, the surface of which is then to be covered with
a ground made of pitch, or pitch mixed with virgin wax dissolved in some suitable
solvent, such as petroleum; this will completely cover up the design or picture that
has been transferred to the surface of the plate, but upon pouring hot water on to
the plate from the height of a few feet, the wax or pitch ground will be softened,
and the soluble crystalline ink of the design or picture will swell up and burst
through the thin film of pitch or other ground, and will be very quickly dissolved
and washed away by the hot water, and all the fine lines of the design will be
exposed and appear through the ground. When this has been effected the pitch or
wax ground may be hardened again by the application of cold water to the surface
of the plate. The design may then be bitten in by means of acid, as in the ordinary
operation of etching on steel or copper plates.
When the drawn pattern contains very fine lines it will sometimes become
necessary to give a little substance to the lines before laying on the pitch or wax
ground; this is effected by dusting over the surface of the plate finely pulverized
soda or other soluble salt, which will adhere to the crystalline ink of the design
provided it be not quite dry and hard. By this means the lines of the design may
be deepened and thickened. The ground may then be put on the surface, and the
process of laying bare and biting in the design may be carried on in the manner
just explained.
It is scarcely necessary to say that if the design to be produced on the plate or
other surface is to be in relief instead of being sunk, such parts as are to be in
relief must be drawn in ink which will not be acted upon either by water or by the
acid used for biting in; this insoluble irrefractory ink will therefore protect such
parts from the action of the acid.

page_text: In carrying out this modification of our Invention the pattern or design may be
drawn in an ink made of pitch or pitch and wax dissolved in petroleum or other
solvent, and reduced to a liquid state, or such a state of consistency as will admit of
its being used by the artist with facility.
If the design is to be drawn by the artist direct on the metal or other surface, the
latter should be prepared by pouring some liquid ammonia thereon, and causing it
(by the application of heat to the under surface of the metal or other plate) to dry
thereon, and produce a thin film which will prevent the ink from "running" or
spreading out laterally.
If the design has been previously drawn on paper or other fabric, and is then to
be transferred by pressure to the metal or other surface, the latter should be first
covered with a film of smoke, so that the lines of the impression should not spread
laterally or leave the metal bare.
The process for removing any soluble substance from the surface of the plate so
as to leave those parts of the surface which are covered therewith exposed to the
action of the acid in "biting in" is the same as when the design is sunk, as in
ordinary engraving, that is to say, the object is effected by means of water, either
poured on as above described, or the article may be immersed therein.
Having now described our Invention of "Improvements in Engraving, both Sunk
and in Relief, on Metal, Stone, and other Hard Substances," and having explained
the manner of carrying the same into effect, we claim as the Invention secured to us
by Letters Patent as aforesaid,―
The process, herein set forth, for engraving or producing patterns or designs on
hard surfaces by means of acids.
We claim particularly the use, in the manner above described, of sugar, gun,
potash, soda, or other substance soluble in water or other liquid for one part of the
process of preparing the hard surface for engraving, in combination with another
substance, such as pitch, wax, or other analogous substance which is insoluble in
water for another part of the preparing process, as and for the purposes herein set
forth.
In witness whereof, I, the said Désiré L'heureux, have hereunto set my hand
and seal, the Seventh day of February, in the year of our Lord One thousand
eight hundred and seventy-eight.
D. L'HEUREUX. (L.S.)