AN IMPROVED PROCESS OF BRONZING, GILDING, AND SILVERING ALL SURFACES IN GENERAL
Year: 1878

page_text: LETTERS PATENT to Louis Préaubert, of Nantes (Loire Inferieure), France,
Ornamental Painter, for the Invention of "AN IMPROVED PROCESS OF
BRONZING, GILDING, AND SILVERING ALL SURFACES IN GENERAL.”
Sealed the 17th September 1878, and dated the 22nd March 1878.
PROVISIONAL SPECIFICATION left by the said Louis Préaubert at the Office
of the Commissioners of Patents on the 22nd March 1878.
LOUIS PRÉAUBERT, of Nantes (Loire Inferieure), France, Ornamental Painter.
"AN IMPROVED PROCESS OF BRONZING, GILDING, AND SILVERING ALL SURFACES IN
GENERAL."
My process of gilding, or of bronzing, which is applicable to wood, cardboard,
leather, marble, metals, papers, stuffs, and to bodies offering a certain resistance,
consists in employing all metals in a pulverulent state, or in powder mixed with a
composition of spirit of wine, gumlac, and essence of turpentine.
The spirit of wine and the gumlac suffice to obtain a good result; one of the
peculiar characters of this process is the employment of any metal whatever in
powder mixed with the substance herein-before stated.
When I employ bronze powder as metallic powder I prepare my mixture with
the substances in the following proportions :-
I commence by dissolving the gumlac in pure alcohol, this liquid having a volume
of about 4 times greater than that of the gumlac; it is in this thick solution thus
obtained that I introduce the bronze powder in the proportion of 1 part of this
powder to 3 parts of the solution. This solution in my process plays a double role;
1st, as a vehicle to deposit the metallic powder; 2nd, as an agglutinant to fix
this powder on the surface to which it is to be applied. These proportions remain
the same for gold, silver, and other metal powders.
The application of this metallic mixture is very simple.

page_text: The surface of the object destined to receive my metallic mixture should be per-
fectly smooth.
When it is for wood, for instance for framings, the mouldings to be metallized are
previously covered with one or more layers of whiting (blanc de meudon) called
Spanish white, and the surface is scraped with a tool cut to correspond with the same
shape as the moulding till the said surface becomes quite smooth and free from holes
or roughness. The surface being thus prepared, the composition or mixture is spread
thereon with a brush, and in coats or layers, as is done in ordinary painting. When
the number of layers appear sufficient the surface is strongly brushed or rubbed to
avoid as much as possible the superposition of the metallic layers.
The effect to be obtained afterwards is another salient character in my process,
for till now it was possible to obtain by means of the mixture a thick bronzey
effect (or an effect of dull or dead bronze), or of some material of any colour, but
by my process the burnishings obtained are as beautiful as on gold, silver, or
platinum used in leaves. Or I obtain this burnishing either by a steel burnisher, as
used by gilders on metals, or by means of a stone burnisher like that usually
employed by gilders. The result of this burnishing is perfect; as an addition to
my process of burnished bronzing I use a metal in white powder; and I burnish it as
herein-before stated, then by means of a special varish I obtain a tone of gold
similar to that now known under the name of chemical gilding. I obtain likewise
by spreading this mixture with the brush the same effect as with gold in leaves,
and with less expense, and with less' labour.
To preserve well my metallic decorations I cover it with a very transparent
siccative varnish so as to preserve the metal powder from contact with the atmos-
phere, and from the change that might result therefrom.
I claim the exclusive working of my process of burnished bronze of any colour
which has for distinctive character,―.
1st. The employment of metallic powders.
2nd. The mixture of these powders with spirits of wine, gumlac, essence of
turpentine, or with a part of these substances which constitute at the same time a
vehicle for the powder and an agglutinant.
3rd. The spreading of this metallic mixture by the brush on the objects to be
bronzed.
4th. The burnishing giving to the result the same aspect as that obtained by
metal in leaf.
And, 5th. As addition to this process the employment of a white metal or
powder with a varnish to obtain a chemical gilding.
This process is applicable to wood, leather, stuffs, marble, metals, paper, cardboard,
and in general to all bodies offering a certain resistance.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Louis Préaubert in the Great Seal Patent Office on the 20th Septem-
ber 1878.
Louis PRÉAUBERT, of Nantes (Loire Inferieure), France, Ornamental Painter.
"AN IMPROVED PROCESS OF BRONZING, GILDING, AND SILVERING ALL SURFACES IN
GENERAL."
My process of gilding, or of bronzing, which is applicable to wood, cardboard,
leather, marble, metals, paper, stuffs, and to bodies offering a certain resistance,
consists in employing all metals in a pulverulent state, or in powder mixed with a
composition of spirit of wine, gumlac, and essence of turpentine.
In any case the spirit of wine and the gumlac suffice to obtain a good result.
One of the peculiar characters of this process is the employment of any metal
whatever in powder mixed with the substances herein-before stated.
When I employ bronze powder as metallic powder I prepare my mixture with
the substances in the following proportions:
I commence by dissolving the gumlac in pure alcohol, this liquid having a volume
of about four times greater than that of the gunilac; it is in this thick solution thus
obtained that I introduce the bronze powder in the proportion of 1 part of this
powder to three parts of the solution. This solution in my process plays a double
role; 1st, as a vehicle to deposit the metallic powder; 2ndly, as an agglutinant to
fix this powder on the surface to which it is to be applied. These proportions remain
the same for gold, silver, and other metal powders.
The application of this metallic mixture is very simple, and the surface of
the object destined to receive my metallic mixture should be perfectly smooth.
When it is for wood, for instance for framings, the mouldings to be metallized are
previously covered with one or more layers of whiting (blanc de meudon) called
Spanish white, and the surface is scraped with a tool cut to correspond with the
same shape as the moulding till the said surface becomes quite smooth and free from
holes or roughness. The surface being thus prepared the composition or mixture
is spread thereon with a brush, and in coats or layers, as is done in ordinary
painting. When the number of layers appears sufficient the surface is strongly
brushed or rubbed to avoid as much as possible the superposition of the metallic
layers.
The effect to be obtained afterwards is another salient character in my process,
for till now it was only possible to obtain by means of the mixture a thick bronzy
effect (or an effect of dull or dead bronze), or of some material of colours, but by
my process the burnishings obtained are as beautiful as on gold, siver, or platinum
used in leaves. Or I obtain this burnishing either by a steel burnisher as used by
gilders on metals, or by means of a stone burnisher like that usually employed by
gilders. The result of this burnishing is perfect; as an addition to my process of
burnished bronzing I use a metal in white powder, and I furnish it as herein-before
stated; then by means of a special varnish I obtain a tone of gold similar to that
now known under the name of chemical gilding. I obtain likewise by spreading
this mixture with the brush the same effect as with gold in leaves, and with less
expense, and with less labour.
To preserve well my metallic decorating I cover it with a very transparent
siccative varnish so as to preserve the metal powder from contact with the atmos-
phere, and from the change that might result therefrom.
Having now described the nature of my said Invention, and in what manner the
same is to be performed, I declare that 1 claim the exclusive working of my pro-
cess of burnisher bronzing of any colours which has for distinctive charactors,―
First. The employinent of metallic powders as and for the purposes set forth.
Secondly. The mixture of these powders with spirits of wine, gumlac, and essence
of turpentine, or with a part of these substances, which constitute at the same time
a vehicle for the powder and an agglutinant as set forth.

page_text: Thirdly. The spreading of this metallic mixture by the brush on the objects to
be bronzed, as set forth.
Fourthly. The burnishing giving to the result the same aspect as that obtained
by metal in leaf.
And, fifthly. As an addition to this process the employment of a white metal or
powder, with a varnish to obtain a chemical gilding, as described.
This process is applicable to wood, leather, stuffs, marbles, metals, paper, card-
board, and in general to all bodies offoring a certain resistance, as herein-before
mentioned.
In witness whereof, I, the said Louis Préaubert, have hereunto set my hand
and seal, this Twelfth day of August, in the year of our Lord One
thousand eight hundred and seventy-eight.
TATTA
Witness,
CH. ARMENGAUD,
Civil Engineer.
LOUIS PREAUBERT.
(L.8.)