IMPROVE- MENTS IN THE PRODUCTION OF COPPER OR OTHER METALLIC PLATES FOR THE PURPOSE OF PRINTING THEREFROM
Year: 1866

page_text: LETTERS PATENT to. Charles Gilpin, Esquire, M.P., of No. 10, Bedford
Square, in the County of Middlesex,, for the Invention of "IMPROVE-
MENTS IN THE PRODUCTION OF COPPER OR OTHER METALLIC PLATES FOR THE
PURPOSE OF PRINTING THEREFROM." -A communication from abroad by
Francis Kossuth and Louis Theodore Kossuth, both of Turin, in the
Kingdom of Italy.
F
Sealed the 27th April 1866, and dated the 13th February 1866.
PROVISIONAL SPECIFICATION left by the said Charles Gilpin at the
Office of the Commissioners of Patents, with his Petition, on the
13th February 1866.
I, CHARLES GILPIN, Esquire, M.P., of No. 10, Bedford Square, in the
County of Middlesex, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN. THE PRODUCTION OF COPPER OR OTHER METALLIC PLATES.
FOR THE PURPOSE OF PRINTING THEREFROM," to be as follows:-
These improvements relate, first, in taking the photographic image of
objects either from nature, such as landscapes, buildings, machinery, or
from pictures, drawings, engravings, geographical or other maps, already
represented on paper or cloth. This photographic image. is produced,
first, for the relievos by taking on a plate of glass a positive image

page_text: obtained by transparency through another negative one (representing
the object to be reproduced in the relievo engraving), on which a striped
plate of glass has closely been applied. This plate of glass may be
striped with lines in the following manner-With a fine diamond point
its surface is covered with two series of parallel stripes or lines crossing
each other at right or acute angles, and in some cases of only one set of
parallel lines crossing in one direction the whole surface of the glass. As
the fineness, the proximity, and disposition of these lines depends on the
requirements of particular cases it will be necessary to hold in reserve a
certain number of these plates variously prepared. These stripes must be
darkened with black mastic or any other suitable dark colored substance.
Second, for the incision engravings from the object to be reproduced
a negative image must first be taken. Since in nature these objects are
evidently not shadowed with lines or dots, if the photographic image is
taken from nature it will be necessary in the first place to take a positive
image by transparency through an inverted negative one, then to apply
one of the above-described black striped glass plates close upon it, and
finally to take through this striped glass a second negative image. If it
be required to reproduce a picture or a drawing which is not shadowed
with lines or dots the striped glass plate, with white instead of black
mastic in its stripes, is applied directly on the objects themselves, and
through it the inverted negative image of these objects is taken; or if they
are of such dimensions that this cannot be done, then an image reduced to
the size required for the engraving must first be taken from them; and,
lastly, if the objects to be reproduced are already shadowed with lines or
dots, or if they do not require shadowing, as in the case of geographical
maps,
lineal drawings, or other similar objects, an inverted negative image
of these objects is simply taken, and the above-described striped glass
plates are not required. To these striped glass plates may be substituted
others on which the negative image of a blackened sheet of paper with
white stripes on it, or a white one with black stripes, has been taken.
Once the photographic image obtained in the above-mentioned way the
same operations will be employed for relievos as for incision engravings.
These operations consist in the following process:-While the photo-
graphic glass plate bearing the positive or negative image (as the case
may require) is still wet it is plunged in a bath heated to a temperature of
158° Fahrenheit or thereabouts, the bath being composed of a mixture
in the following proportions or thereabouts,-1000 parts of water, 150
parts bichromate of potash, and 60 parts gelatine. Immediately after

page_text: having taken out the glass plate of this bath a mixture made of the same
ingredients in the following proportions or thereabouts, vizt., 100 parts
water, 18 parts saturated solution of bichromate of potash, and 25 parts of
gelatine, is poured on it to an uniform height. This layer once cooled
the image glass plate thus prepared is exposed to the action of light in a
frame or holder of rectangular or other suitable shape, the bottom of
which is blackened. After the necessary lapse of time the image glass
plate is taken out of the frame, plunged in moderately warm water, and
left there for a while. Once taken out of this bath the image glass plate
is put into another and much warmer bath of pure water. After having
remained there for a short period of time it is plunged into another bath
composed of 100 parts of water and 5 parts of tannic acid, or into a bath
composed of 100 parts of water and 10 parts of glycerine, or thereabouts,.
mixed together, and left to remain in this bath for a certain time. Once
the image glass plate has been taken out of this bath and perfectly dried.
a saturated solution of nitrate of silver in alcohol of 40° is passed on it with
a brush several times successively. After this, when dry, it is exposed to a
current or fumigation of hydrogen or sulphurated hydrogen, which reduces
the silver salt and renders the image glass plate a perfect conductor of
electricity; this done, the image glass plate is galvanized in the ordinary
way of galvanoplating, and thus a copper or other metal plate, whether in
relievo or in incision, will be obtained, which can easily be separated from
the image glass plate, and which will serve all the purposes of printing to
which engraved metal sheets in relievo and in incision are applicable. This
process is not only applicable to the production of engraved plates (as well
in incision as. in.relievos) for the use of printers and publishers, but is also
applicable to the production of surfaces for printing on calico, paper, or
other materials, as well as to other industrial purposes.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Gilpin in the Great Seal Patent Office on the
10th August 1866.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
GILPIN, Esquire, M.P., of No. 10, Bedford Square, in the County of Mid-
dlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date, the Thirteenth day of February, in the year of our

page_text: Lord One thousand eight hundred and sixty-six, in the twenty-ninth
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Charles Gilpin, Her special licence that I, the
said Charles Gilpin, my executors, administrators, and assigns, or such
others as I, the said Charles Gilpin, 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 "IMPROVEMENTS IN THE PRODUCTION OF COPPER OR OTHER
METALLIC PLATES FOR THE PURPOSE OF PRINTING THEREFROM," a communication
to me from abroad by Francis Kossuth and Louis Theodore Kossuth, both
of Turin, in the Kingdom of Italy, upon the condition (amongst others)
that I, the said Charles Gilpin, 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 performed, 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.
NOW KNOW YE, that I, the said Charles Gilpin, do hereby declare
the nature of the said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement thereof, that is to say :-
These improvements relate, first, in taking the photographic image of
objects either from nature, such as landscapes, buildings, machinery, or
from pictures, drawings, engravings, geographical or other maps, already
represented on paper or cloth. This photographic image is produced,
first, for the relievos by taking on a plate of glass a positive image obtained
by transparency through another negative one (representing the object to
be reproduced in the relievo engraving), on which a striped plate of glass
has closely been applied. This plate of glass must be striped with lines
in the following manner:-With a fine diamond point its surface is covered
with two series of parallel stripes or lines crossing each other at right or
acute angles, and in some cases of only one set of parallel lines crossing
in one direction the whole surface of the glass. As the fineness, the
proximity, and disposition of these lines depends on the requirements of
particular cases, it will be necessary to hold in reserve a certain number of
these plates variously prepared. The stripes must be darkened with black
mastic or any other suitable dark coloured substance.

page_text: Second, for the incision engravings from the object to be reproduced
a negative image must first be taken. Since in nature these objects are.
evidently not shadowed with lines or dots, if the photographic image is
taken from nature it will be necessary in the first place to take a positive.
image by transparency through an inverted negative one, then to apply.
one of the above-described black striped glass plates close upon it, and.
finally to take through this striped glass a second negative image. If it be-
required to reproduce a picture or a drawing which is not shadowed with
lines or dots the striped glass plate, with white instead of black mastic in-
its stripes, is applied directly on the objects themselves, and through it the
inverted negative image of these objects is taken, or if they are of such
dimensions that this cannot be done, then an image reduced to the size,
required for the engraving must first be taken from them; and, lastly, if
the objects to be reproduced are already shadowed with lines or dots, or if
they do not require shadowing, as in the case of geographical maps, lineal:
drawings, or other similar objects, an inverted negative image of these objects
is simply taken, and the above-described striped glass plates are not required.
For these striped glass plates may be substituted others, on which the:
negative image of a blackened sheet of paper with white stripes on it, or a
white one with black stripes, has been taken. Once the photographic.
image obtained in the above-mentioned way the same operations will be:
employed for relievos as for incision engravings. These operations consist,
in the following process: While the photographic glass plate bearing.
the positive or negative image (as the case may require) is still wet it is,
plunged in a bath heated to a temperature of 158° Fahrenheit, or there--
abouts, the bath being composed of a mixture of 1000. parts water, 150°
parts bichromate of potash, and 60 parts-gelatine or thereabouts. Imme-
diately after having taken out the glass plate of this bath a mixture made:
of the same ingredients, 100 parts water, 18 parts saturated solution;
bichromate of potash, and 25 parts gelatine, is poured on it to an uniform
height. This layer. once cooled the image glass plate thus prepared is
exposed to the action of light in a frame of suitable shape, the bottom of
which is blackened. After the necessary lapse of time the image glass,
plate is taken out of the frame, plunged in moderately..warm water or
about 100° Fahrenheit and left there for a while.. Once taken out of this
bath the image glass plate is put into another and much warmer bath or
of about 194° Fahrenheit of pure water. After having remained there for
a short period of time it is plunged into another bath composed of about
100 parts of water and 5 of tannic acid, or .of. about 100 parts, of water;

page_text: and 10 parts or thereabouts of glycerine mixed together, and left to remain
in this bath for a certain time, 2 or 3 hours. Once the image glass plate:
has been taken out of this bath and perfectly dried a saturated solution of
nitrate of silver in alcohol of 40° is passed on it with a brush several times
successively. After this, when dry, it is exposed to a current or fumigation
of hydrogen or sulphuretted hydrogen, which reduces the silver salt and
renders the image glass plate a perfect conductor of electricity. This
done the image glass plate is galvanised in the ordinary way of galvano
plating; and thus a copper or other metal plate, whether in relievo or in
incision, will be obtained, which can easily be separated from the image
glass plate, and which will serve all the purposes of printing to which
engraved metal sheets in relievo and in incision are applicable. This
process is not only applicable to the production of engraved plates (as
well in incision as in relievos) for the use of printers. and publishers, but
is also applicable to the production of surfaces for printing on calico,
paper, or other materials, as well as to other industrial purposes.
And in order that the Invention may be most fully understood, and
that the same may be carried out in practice, the following explicit
description is given:-The Invention herein-after described under Sections
or Articles 1, 2, and 3, consists, firstly, in an improved process or processes
for the production of surfaces in "intaglio" and "relievo" by the agency
of photography and the action of light on layers of sensitised organic sub-
stances. Secondly, in an improved process or processes for the production
on the same surfaces of shading lines or dots similar to those employed in.
the engravings executed by the burine or those called "mezzotints."
Thirdly, in a new process or processes for the production by galvano-
plasty of metallic surfaces engraved in intaglio or relievo, or also in the
application of a certain substance or of a certain class of substances, and in
a certain manner (all described, herein-after) to the galvanisation of surfaces
in intaglio or relievo obtained by the agency of photography and the action.
of light on layers of sensitised organic substances, and, lastly, in the appli-
cation of this substance and of this class of substances for the galvanisation
of organic substances in general.
Section or Article 1 describes the production of the helioplastical plate
for engravings in intaglio. The first part of this section relates to the
reproduction of engravings executed and shadowed with lines or dots
forming a "grain" of any kind.
(No. 1.)--For the reproduction of engravings or drawings the outlines:
and shadows of which are executed with lines or with dots. forming a

page_text: "
grain," the operator first takes by the ordinary means of photography
a reversed negative image of the object, which image will require to be
very distinct and well defined.
Process (No. 2.) To produce the helioplastical image take ordinary
gelatine, cut it to pieces, and place it in a cup protected from the action
of light. Then afterwards prepare a mixture of 100 parts of water and
18 parts of saturated solution of bichromate of potash, pour this mixture
on the gelatine, and allow this latter to remain under the action of the
bichromate for several hours; when the gelatine has absorbed a sufficient
quantity of bichromate decant the excess of the solution, and melt the
gelatine thus prepared in a bath of hot water, and finally filter it through
a piece of linen or flannel. After the gelatine has been prepared as
ábove described, in order to form the helioplastical surface the operator
may proceed as has been hitherto done, that is to say, he may spread a
layer of bichromatized gelatine on a plate of metal or glass, apply on this
layer a photographical "cliché," and cause the impression of light to be
produced through this "cliché." This process however is not preferred,
as it causes great inconveniences. In fact, however great the attention
may be with which the photographical "cliché" is applied on the
gelatinised plate, it will be very difficult to prevent air bubbles being
interposed between the two plates. And again, if the layer of gelatine
is allowed to coagulate before applying the "cliché" on it the gelatine
when coagulating very often forms a wavy rimpled surface, and hence
the "cliché" and this surface cannot be made to coincide entirely. If,
on the contrary, the gelatine is not allowed to coagulate before the
"cliché" is applied on it the gelatine while coagulating would adhere
to the "cliché"; this adherence would still more be augmented if the rays
of the sun during exposure were to heat the back of the "cliché"; now.
when the plate bearing the gelatine has to be separated from the "chiché "*
this latter will tear away a part of the gelatine layer, and thus will spoil:
the perfection of the helioplastical image. If, instead of pouring the
bichromatised gelatine on another glass or metal plate and applying
afterwards the photographical "cliché" on it, the gelatine is poured.
directly on the "cliché," on that part of the photographic glass plate which
bears the collodion film, then the gelatine while warm will adhere power-
fully to the collodion, will penetrate its pores, and on coagulating the
molecular attraction between the layer above the collodion film and the
particles of gelatine penetrated into the pores of this film will almost in.
every case (as the gelatine on. coagulating contracts powerfully) tear the

page_text: thin film of collodion, and when after exposure the helioplastical image
shall have to be developed by melting those parts of the gelatine which
have not received the impression of light the dissolvent would inevitably
"wash off the collodion film together with the gelatine attached to it. If
again the bichromatised gelatine were poured on the opposite side of the
photographical glass plate to that which bears the collodion, when during
exposure the rays of light on penetrating through the image on the
collodion would before reaching the gelatine layer have to pass through
the body or thickness of the plate, and be deviated in such a maner as
never to form a distinct and perfect fac-simile of the image on the collodion.
The next step of the improved process to overcome the difficulties just
described is the following:-When the photographical "cliché" is made,
plunge it into a bath composed of about 1000 parts of water, 150 parts of
-bichromate of potassa, and 60 parts of gelatine. Leave the "cliché" in the
bath heated to a moderate temperature for about ten minutes. After this
time take the "cliché" out and place it in a hollow box with a shutter,
the bottom of which where the "cliché" reposes having previously been
placed in a horizontal position, as is well understood. When the "cliché "
is thus disposed the bichromatised gelatine produced, melted and filtered
as above described, has to be poured on the "cliché" up to such a height
or thickness as will be required by the highest parts in relievo of the
helioplastical image (that is to say, the gelatine should be poured on that
side of the photographic glass plate where the collodion film is).
The effect of the preliminary bath of gelatine is the following:-When
the "cliché" is put into it the pores of the collodion film expand and get
entirely filled with the solution, which penetrates even between the
collodion film and the surface of the glass, and makes the absorbtion of
the very much denser gelatine layer impossible. Now after this layer has
been spread on the "cliché" as above described, and when coagulation
takes place, the particles of the preliminary bath of gelatine which fill the
pores of the collodion film will suffer a much slighter contraction and
certainly not sufficient to tear the film, but sufficiently so for connecting
powerfully the gelatine layer with the collodion film.
When the gelatinisation is finished the "cliché" is exposed to the action
of light in order to produce the helioplastical image. For this purpose a
flat box is employed, the sides of which are cut to a slope; one of the
sides of the box is moveable, so as to make the box itself serviceable for
glass plates of different dimensions; on each of two opposite sides a spring
is fixed in order to hold the glass plate in its place. All the inner sides.

page_text: of the exposition box must be black in order not to refract light. The
time of the exposure must be regulated by the power of the image required
to be produced. When the impression has been esteemed sufficient the parts
of the gelatine impressed by light can be developed into an helioplastical
image by two processes, either by making the parts non-impressed swell in
a bath of cold water, or to dissolve them; in the first case the helioplastical
image will appear sunken, while in the other in relievo. The process of
dissolving is far the more perfect, for if the non-impressioned parts of the
gelatine are made to swell their swelling takes place not only in a vertical
but also in a lateral sense, and hence the distinctness of the finer lines is
obliterated.
The process for developing the helioplastical image is to dissolve the
non-affected parts of the gelatine in two series of baths, the first of moderate
heat, the second almost boiling. When the non-affected parts get entirely
dissolved the helioplastical image will come forth, if the plate is allowed to
dry, with remarkable clearness and perfection. When in this state the
helioplastical plate is ready for the treatment herein-after described.
The 2nd part of Section or Article 1 describes the production of helio-
plastical images for engravings in intaglio after nature, or after a painting,
or whatever other object the outlines, and the shadows, of which are not
formed with the lines or dots forming the "grain" of the engravings done
by ordinary processes.
Preliminary Observations:-It is evident that if an image were to be
engraved, as it is in nature, without breaking up the shadows and half
tints with lines or dots, the simply sunken surfaces in the metal would not
present a sufficient hold to the printers' ink or colour, and all distinctness
in the impression would be impossible. To produce these lines or dots
(this indispensable "grain," without which engraving after nature would
be impossible) many unsuccessful attempts have been made. . This grain
may be produced in different ways according to this Invention, as
follows:-
(No. 1.) In order to engrave in intaglio a photographic image, a.
painting, or other picture whatever, the outlines and shadows of which
are not represented by lines or dots forming a certain "grain," and the
dimensions of which are not very considerable, against the surface of
these pictures a plate of glass is applied on which has been drawn with.
a fine diamond point, or in any other manner, two series of parallel lines
cutting each other at the required angle and drawn at the required uniform.
distances. These lines are made photogenic or antiphotogenic according

page_text: to the requirements of the particular case by introducing into these lines
white or black varnish, mastic, or any other suitable substance. The
striped side of the glass plate must be turned inside and applied on the
picture. In this manner the photographic image of the picture and of the
grain is taken simultaneously.
(No. 2.) From photographic "clichés " an image is produced directly
with an artificial grain on it by applying on the collodionised side of this
"cliché" the striped glass plate, and on reproducing the two simultaneously
by transparency.
(No. 3.)-Instead of the glass plates with stripes engraved on them a
simple photographic "cliché" can be employed, on which the image of a
grain previously lithographised on paper has been taken. The grain on
the paper will have been formed of photogenic lines on antiphotogenic
ground or of antiphotegenic lines on photogenic ground as required.
'
(No. 4.) The process to which the most importance is attached is
the following:-In order to engrave after nature a landscape, portrait,
machinery, oil paintings, or other objects, and in order to produce any
required grain at the same time as the image of the object itself is taken,
a photographical apparatus is employed, the camera of which has two object
glasses opposite to each other and placed on the same optical axis; these
object glasses are moveable backwards and forwards as the focussing glass is
in ordinary photographical cameras, and can be fixed in a similar manner.
The focussing glass is roughened or depolished only at one of its sides, is
fixed in the middle of the camera, being, however, naturally moveable in the
vertical sense. The plates bearing the object glasses can also be removed
together with them, so as to allow the operator to put to focus the image
of the object on one side and that of the grain on the other, both of which
being formed on the same side of the focussing glass, and hence on the
same collodion film. The grain printed on a sheet of paper is fixed on a
Board, which is placed on a stand so as to have its surface vertical to the
focus of the lenses. This stand is moveable. In large machines an opening
can be made on each side of the focussing glass, which opening can
evidently be closed with perfection during the operation. The focussing
may also be effected on both sides by a refracting mirror. (The form of
the apparatus may be varied considerably with more or less advantage
without limiting this part of the Invention to the exact arrangements
previously described.) If, then, it is required to represent on the same
"cliché" simultaneously the object and the "grain," the double apparatus
must be turned. with one of its object glasses towards the object to be

page_text: "
board
reproduced and the other towards the stand supporting the "grain
or surface. The distance of this stand is be regulated by the fineness or
roughness required for the grain. The two images are put to focus on the
focussing glass, and are simultaneously taken on the same collodion film by.
the ordinary process of photography.
(No. 5.) When the photographical image with the grain on it has been
produced the "cliché" is submitted to the same manipulation as described
in the second paragraph of the 1st part of this Article, and after expo-
sition the grain will be obtained in relief in all the shadowy parts; the
height of the relief will diminish in the half-tints and disappear altogether
in the lighted parts of the image.
(No. 6.) Since the engravings done by the ordinary processes are
shadowed either with lines or with dots, the grain that has to be repro-
duced on the "cliché" must be composed of photogenic lines on an
antiphotogenic ground when the shading is required to be made with
lines and of antiphotogenic lines on photogenic ground if the shading has
to be executed with dots.
Section or Article 2. Engravings in relievo.-Description of the mode
of producing the helioplastical "cliché" for the engraving in relievo.
The first part of this Section relates to the reproduction of drawings,
prints, etc., executed with lines or other "grain."
(No. 1.) To engrave in relievo drawings and prints of every sort, the
outlines and shadows of which are represented by lines or dots, by the
ordinary process of photography, a negative image is taken of the drawing
or print, and after this "cliché" is produced by transparency another.
ordinary positive photographical "cliché."
(No. 2.) To produce the helioplastical image the operator proceeds
entirely as has been described in Section or Article 1 (First Part, No. 2)..
It is evident that on the helioplastical image all parts that have to
appear in white on the print, and which hence must be sunken on the
metal plate engraved in relievo, will be impressioned by the rays of light
which are made to pass through the positive "cliché," and hence will not
dissolve in the baths of hot water and will remain in relievo on the helio-
plastical image, and hence will be sunken on the metal plate, whereas all
the opaque parts of the positive "cliché" which represent the blacks of the
image, and in consequence will have to stand out in relievo on the metal
plate, will be sunken on the helioplastical "cliché," for the gelatine will
be protected from the action of light in all these parts by the opaque lines
of the positive "cliché," and hence will dissolve in the baths of hot water

page_text: and will dissolve down unto the surface of the glass plate itself, making
thus all the lines of the relievo whether thick or thin stand out to the
same height, while the sunken interstices between them on the metal plate
will not be of equal depth.
The second part of this section relates to the production of engraving
in relievo after nature, or after an oil or water colour painting, or whatever
other object on which the outlines and the shadows do not consist of lines.
or dots forming a "grain."
In order to engrave these objects in relievo the operator must proceed
as described in Section or Article 1 (2nd Part, Nos. 1, 2, 3, and 4). To
produce the negative image by photography from this negative "cliché".
a positive one is taken, and this positive must be operated upon as
described in Article 1 (2nd Part, No. 5).
Section or Article 3 describes the preparation of the helioplastical plate
for direct galvanisation.
(No. 1.) When the helioplastical image in intaglio or relievo has been.
produced in the way previously described in Articles 1 and 2, the helio-
plastical "cliché "is placed in a bath composed of water and tannic acid,
or water and glycerine. The proportions of these mixtures varies according
to the different heights required to give to the relievos or depth to the
intaglios produced according to this Invention, which height and depth
increases in direct ratio with the per-centage of glycerine or tannic acid
in the water. Both of these baths must be heated moderately before
being used, and the "clichés" will have to remain in them not less than
one hour, but the action of the baths may be prolonged much beyond this
time without prejudice to the helioplastical plate..
:
(No. 2.) When the helioplastical "cliché" is taken out from the bath
of tannic acid or glycerine it is dried and rendered a conductor of elec
tricity by being coated with a solution of nitrate of silver in concentrated
alcohol, and afterwards submitted to vapours of sulphuretted hydrogen,
which reduce the silver salt. The action of these vapours will be com-
pleted when the plate has acquired a shining metallic lustre.
(No. 3.) When the process is brought to this stage the metallised
"cliché" is ready for receiving the galvanic deposit which will constitute
the metal plate engraved in intaglio or in relievo, according to what the
helioplastical "cliché" was prepared for; but in order that galvanisation
should take place with, more regularity and uniformity on the whole surface
of the metallised "cliché," and that when the deposit is considered suffi-
ciently thick that the metal plate should be easily separated from the

page_text: glass on the four edges of the metallised "cliché," a thin and narrow sheet
of metal is applied, and this narrow sheet of metal is covered with wax or
varnish capable of isolating it. When the thickness of the galvanic deposit
is considered sufficient the glass plate is separated from the metal plate ;
the metallised gelatine which adheres to this latter is washed off with a
fine brush and hot water, and the metal plate is cleaned in the ordinary
manner used by engravers. It will then be ready for printing from.
It should be distinctly understood that for the purpose of producing by
any chemico-physical or artificial process engraved metal surfaces fit for
printing therefrom, as also for the purpose of galvanising directly organic
substances in general for the said purpose, the exclusive use is hereby
claimed not only of the glycerine but also of its compounds and of its
substitutes produced by the saponification of fatty substances, for all these
bodies would act on the same principle on organic substances as glycerine
does, a principle for the practical application of which to the production
of metallic printing surfaces as herein described by the agency of nature,
as also to the galvanisation of organic substances in general for the pro-
duction of printing surfaces as herein described, is distinctly claimed under
the above in part recited Letters' Patent.
The exclusive use of the processes herein described in Sections or
Articles 1, 2, and 3, are also claimed under the grant of the above in part
recited Letters Patent.
In witness whereof, I, the said Charles Gilpin, have hereunto set my
hand and seal, this 27th day of July, in the year of our Lord
One thousand eight hundred and sixty-six.
Witness,
J. G. TONGUE,
Patent Agent,
CHARLES GILPIN. (L.s.)
34, Southampton Buildings,
Chancery Lane, W.C.