IMPROVEMENTS IN ENGRAVING GLASS AND CRYSTALS.
Year: 1856

page_text: LETTERS PATENT to Charles Durand Gardissal, of 10, Bedford Street,
Strand, London, and 29, Boulevart St. Martin, Paris, Patent Agent,
for the Invention of "IMPROVEMENTS IN ENGRAVING GLASS AND CRYSTALS.
A communication.
Sealed the 28th November 1856, and dated the 25th June 1856,
PROVISIONAL SPECIFICATION left by the said Charles Durand Gardissal
at the Office of the Commissioners of Patents, with his Petition, on the
25th June 1856.
I, CHARLES DURAND GARDISSAL, of 10, Bedford Street, Strand, London, and
29, Boulevart St. Martin, Paris, Patent Agent, do hereby declare the nature
of the said Invention for "IMPROVEMENTS IN ENGRAVING GLASS AND CRYSTALS,"
to be as follows:-
This Invention consists of depositing upon glass or crystal fatty or resinous
matters on such parts as are not to be engraved, the engraving patterns
or designs being effected by the action of hydrofluoric acid on the said glass
or crystals. The said fatty or resinous matters are deposited in manner
following:-
1st, for plane or curved articles of glass or crystal, by means of transferring
a print or using a lithographic stone engraved, & taking care to cover the
spaces to be left in blank with the said fatty or resinous matter.

page_text: 2nd, for plane surfaces, by means of a layer of fatty or resinous matter, on
which the designs or patterns are made with metal plates with the patterns cut
out; the fatty or resinous matter is made to adhere by being spread in
a heated state.
3rd, by means of fatty or resinous substances reduced to a powder, spread
through a sieve on the surface of the said articles to be engraved through
metal plates with the designs cut out, or through open work stuffs, paper
cuttings; the said fatty or resinous substances being, as aforesaid, spread
while in a hot melted state.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Durand Gardissal in the Great Seal Patent Office on
the 24th December 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
DURAND GARDISSAL, of 10, Bedford Street, Strand, London, and 29, Boulevart
St. Martin, Paris, Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-fifth day of June, in the year of our Lord
One thousand eight hundred and fifty-six, in the twentieth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Charles Durand Gardissal, Her special licence that I, the said Charles Durand
Gardissal, my executors, administrators, and assigns, or such others as I, the
said Charles Durand Gardissal, my executors, administrators, 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 "IM-
PROVEMENTS IN ENGRAVING GLASS AND CRYSTALS," a communication, upon the
condition (amongst others) that I, the said Charles Durand Gardissal, my
executors or administrators, by an instrument in writing under my, 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 per-
formed, 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.

page_text: NOW KNOW YE, that I, the said Charles Durand Gardissal, do hereby
declare the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:
My Invention relates to certain improvements in engraving glass and
crystal by the aid of "resists" or "reserves," as will be herein-after described.
In this Specification it will be understood by "reserve" the substances used to
prevent or resist the action of the hydrofluoric acid on the bodies which may
be acted on by it. The three various processes which I adopt to obtain the
said reserves for engraving on glass and crystal, and which constitutes this
Invention, are as follows:-
The first process consists in obtaining the reserve, by distributing fatty or
resinous matters reduced to powder, through fabrics or perforated tissues
or substances, on the surfaces which are to be acted on or engraved by the
action of hydrofluoric acid.
The second process consists in obtaining the reserve with a layer of fatty or
resinous matters spread over the surface of the articles to be acted on or en-
graved by the action of hydrofluoric acid. This layer is afterwards ornamented
by means of perforated vignettes or designs.
The third process consists in obtaining the reserve by the transfer of
printings made of fatty or resinous matters, this transferring taking place
on the articles or materials which are to be engraved by the action of hydro-
fluoric acid.
The first and second process are chiefly applicable to plane surfaces; the
third is applicable to both plane and curved surfaces.
According to the first process I obtain the reserve by means of fatty or
resinous powders, as follows:-The matters used for obtaining this reserve
must be capable of being melted and reduced to powder or dust. Various
materials have the said properties, such as colophone mixed with bees-wax,
damnare resin mixed with bitumen of Judea, and bitumen of Judea mixed
with a gum called "elémi."
The mixture which I use by preference is prepared as follows:-I take
one part of soft "elémi," filtered through a linen cloth, and after putting
it over the fire add two parts of bitumen in powder, stirring the mixture
all the time with a spatula till the whole is completely melted; after which I
pour this mixture, while still warm, on a cast-iron plate, where it cools; after
cooling I pulverize or reduce it to as fine a powder as possible.
In order to apply the powder, thus obtained, I rub the substance, on which
the same is to be deposited, with oil or essence of turpentine; I place on this

page_text: substance a perforated or bored design, either in cloth or paper, or any other
suitable substance capable of presenting a thin and even coating; this done, I
spread the powder on the design, in a layer of equal and sufficient thickness,
which I effect either by placing the substance to be coated under a sieve con-
taining the powder, by or introducing the same horizontally in a box, in the
interior of which the above powder is introduced and put in motion or
agitation. The vacant spaces of the design thus determined are coated by the
deposit of the powder; I now remove the perforated design, and then heat the
article on which I have operated in order to melt the material forming the
reserve, which takes place without alteration of its outline; after this I
submit the article to the action of the acid, using the ordinary means
for engraving substances which have received reserves or spares
ordinary means.
the
The second process consists in producing the spare or reserve by means of a
coating or layer of fatty or resinous matter, by means of ornamental perforated
designs or vignettes, as follows:-The substance which composes the coating is
the same as that before referred to in carrying out the process above described.
I crush this material with a mullar, moistening it, at the same time adding
a very small quantity of soapy water; I afterwards spread it on the surface to
be engraved, so as to form a thin and equal coating; when this coating is dry
I apply the perforated vignette or ornament on it, and with a fine close brush
I take up what may be removed through the apertures of the vignette.
When the design is so formed, I submit the article or surface so coated to
a sufficient heat to melt the material of the reserve or spare; afterwards I
retouch it, if necessary, and then submit it to the action of the acid to effect
the engraving. The vignettes or design plates must be thin, and at the same
time sufficiently rigid to produce clean and pure designs or images and to
resist the action of the brush. Brass or copper is the material I use by
preference for this purpose.
The third process, which consists in obtaining the reserve or spare by the
transfer of printings made with fatty or resinous matters, is as follows:-The
printings or designs, made by means of metal plates or lithographic stones,
engraved of a depth of two seventy-fifths of an inch. I use brass or steel
plates when I desire to obtain very fine and close lines, but the lithographic
stone will answer the purpose when wider lines and forms are alone required.
I engrave the lithographic plates by means of fatty reserves or spares and
dilute muriatic acid. The reserves are obtained by the bitumen dissolved in
essence of turpentine, which I apply by means of a brush. The engraved stone
or plate receives a coating of ink which is to give the impression. This ink is

page_text: composed of a mixture as follows:-Of bitumen, three parts; essence of
turpentine, three parts; and stearine, two parts. The mixture is heated till
completely melted, and then filtered, and afterwards cooled; it produces a very
thick ink, which is spread on the plate with a flexible knife; I then pass
horizontally over this plate a metallic rule or slide, at the same time exerting
sufficient pressure to take up the ink on the high parts of the plate or stone,
leaving it in the hollow parts only. I apply on the plate, thus engraved and
coated, a thin and sized sheet of paper, without any other preparation, and I
submit the said plate to direct pressure. A screw press, the upper plate of which
is furnished with some thicknesses of cloth or of india-rubber, gives a good
result; but any other suitable means may be employed. After having drawn
back the plate, I now take off the paper, which has thus received a considerable
thickness of ink; I wet this paper so coated with the ink in water weakly
acidulated with hydrochloric acid; I next place it over the surface of a water
bath, heated to the temperature of about 120° or 130° Fahrenheit. These
two operations have for their object to reduce or weaken the adhesion of the
ink to the paper. When this result is arrived at, I apply the paper to the
surface to be engraved, this latter having previously received a thin coating
of oil or turpentine; I then apply a slight pressure with a cylindrical
pad in order to fix the ink; I then remove the paper, and the reserve is
now deposited; some hours are required for drying the ink to ensure
its adhesion to the article or surface which receives it. The surface, after
having been retouched, if necessary, is submitted to the action of the acid,
either by immersion or by partially covering it with the acid. The contact of
the acid may be continued for some hours, and numerous washings take place
without injury to the reserves.
By the above processes complicated designs are as easily produced as designs
of the simpler kinds, while at the same time they are of a nature to extend the
art of engraving on glass and crystals by means of hydrofluoric acid. By this
means white glass, colored glass in one or more layers and colours, plate and
"looking glasses" and plate glass, either polished or unpolished, and generally
the products of crystal and glass works, such as drinking glasses, lamp or light
shades, and other articles, either in a polished or unpolished state, which have
heretofore been ornamented, at great expense, by the wheel engraving or by
hydrofluoric acid engraving, may thus be easily and cheaply engraved or
ornamented.
Having described the nature of my Invention, and the manner of performing
the same, I wish it to be understood that what I claim as my Invention is,
engraving glass and crystal with hydrofluoric acid by the means or aid of

page_text: "reserves, "spares," or "resists," obtained or produced by either of the three
processes, as herein-before described.
In witness whereof, I, Charles Durand Gardissal, have hereunto set my
hand and seal, this Twentieth day of December, in the year of our
Lord One thousand eight hundred and fifty-six.
C. D. GARDISSAL. (L.B.)