A PROCESS FOR REPRODUCING PHOTOGRAPHIES, DRAWINGS, PAINTINGS, AND ENGRAVINGS ENGRAVED ON METAL
Year: 1862

page_text: PROVISIONAL SPECIFICATION left by Fortune Hippolyte Fontaine at
the Office of the Commissioners of Patents, with his Petition, on the
13th March 1862.
I, FORTUNE. HIPPOLYTE FONTAINE, of No. 15, Passage des Petites Ecuries,
in the City of Paris,, in. the Empire of France, do hereby declare the nature
of the said Invention for "A PROCESS FOR REPRODUCING PHOTOGRAPHIES, DRAWINGS,
PAINTINGS, AND ENGRAVINGS ENGRAVED ON METAL," to be as follows:-
I propose to reproduce the subjects set forth in the above title both nega-
tively and positively, the preparation and, modus operandi where not otherwise
directed to be similar to those in known use, and the propertions are only here
given approximately. In reproducing engraved plates by negative stereotypes
I pour upon a zinc plate a solution composed of distilled water about two
ounces, gelatine about one quarter of an ounce, and saturated solution of
bichromate of potash about one-fifth of a cubic inch; when dry, I place the
gelatinous surface of the plate in contact with the printed side of the negative
stereotype on glass or paper of the drawing to be reproduced, exposing it to
sunlight about seven minutes, or diffused light about twenty minutes; I then
remove the zinc.on which the negative stereotype will now be apparent, and
immediately place it in a basin of lukewarm water to dissolve the bichromate,
and in a few minutes the picture will appear engraved in depth sensible to the
touch; I then drain the plate and sponge it with tissue paper, then pour upon
the picture or impression a solution of gallic or perogallic acid, and again wash
the plate. I now have a stereotype, the hollows or cavities of which are solidi-
fied. I take an impression from this by pouring on the stereotype dissolved and
thoroughly purified gutta percha; when this is dry I take a cake of pure gutta

page_text: percha (a little larger than the stereotype) which in. its preparation has been
melted with about three times its weight of linseed or other thick drying oil.
The surface of this cake is heated by a red hot iron, and applied on the stereo-
type in such wise that the coat of purified gutta percha already on the
stereotype unites with the cake. I submit the whole to pressure, and permit
it to cool; I then remove the pressure, and the solidified stereotype being
incompatible with the gutta percha, it follows that I easily. detach from the
primitively engraved stereotype a second one in gutta percha, which reproduces
the picture or engraving in relief. After having submitted the gutta percha
stereotype to the requisite preparations, I place it in a galvanic bath, and thus
obtain an engraved copper plate, reproducing the original with exactness and in
such reduced proportions as may be desired.
I will now describe the reproduction of engraved plates by positive stereo-
types, premising that all the preparations are made both in this and the
preceding case in obscurity, and that the operation takes place with daylight
excluded. I pour upon a prepared copper plate distilled water about two
ounces, gelatine about two drachms, saturated solution of bichromate of potash
about a quarter of a cubic inch, and gum arabic about fifteen grains; I place
the gelatinous surface of the copper plate (when perfectly dry) in contact with
the printed side of the positive stereotype on glass or paper of the design or a
picture to be reproduced, exposing it in sunlight about ten minutes, or in
diffused light from forty to fifty minutes; I then remove the copper plate upon
which the image of the positive stereotype will now be apparent in all its
details, and pour upon it a solution of perchloride of iron, spreading it with a'
brush; this solution expands little by little, the unimpressed or soluble parts
of the gelatine dissolves, the bichromate and prepares the way for the acid; by
which I hollow out the picture or image in presenting it in relief to its action."
When the design appears displayed in relief, I replace the saturated solution
of perchloride diluted with thirty per cent. of distilled water, operating as.
before. Shortly the design begins to develop itself in black, which indicates 3
the beginning of the action of the acid on the copper; I permit the acid to
act until the entire design or picture is devoloped, and after a general action of
several minutes the picture is engraved; I pour off the acid, wash with water,
and the plate is ready for impression and the reproduction of copies identical
with the original.
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