IMPROVEMENTS IN PRODUCING
Year: 1874

page_text: LETTERS PATENT to Eugenio de Zuccato, of Padua, in the Kingdom
of Italy, and of Frith Street, Soho, in the County of Middlesex, in
the Kingdom of Great Britain, Licentiate of the University of
Padua aforesaid, for the Invention of "IMPROVEMENTS IN PRODUCING
COMPLETE SPECIFICATION filed by the said Eugenio de Zuccato at
the Office of the Commissioners of Patents, with his Petition and
Declaration, on the 28th March 1874, pursuant to the 9th Section
of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EUGENIO
DE ZUCCATO, of Padua, in the Kingdom of Italy, and of Frith Street,
Soho, in the County of Middlesex, in the Kingdom of Great Britain,
Licentiate of the University of Padua aforesaid, send greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS IN
PRODUCING FAC-SIMILE COPIES OF WRITINGS, DRAWINGS, AND DELINEATIONS," and
have petitioned Her Majesty to grant unto me, my executors, admini-

page_text: strators, and assigns, Her Royal Letters Patent for the same, and have
made solemn Declaration that I am the true and first Inventor thereof.
NOW KNOW YE, that I, the said Eugenio de Zuccato, do hereby
declare that the following Complete Specification, under my hand and
seal, fully describes and ascertains the nature of the said Invention and
in what manner the same is to be performed in and by the following
statement:-
-
My Invention has reference to the employment of chemical agency in
producing fac-simile copies of writings, drawings, and delineations in
manner herein-after described.
In the first place it is requisite to obtain a thin sheet of paper, close
in texture, and which has been highly sized and well rolled, and is of
the substance or thickness generally known in commerce as bank post.
Other kinds of paper may prove a substitute, but I recommend as being
best adapted for the purpose of my Invention the use of such paper as
I have described.
In the next place the sheet of paper before described should upon one
side be entirely covered or coated with an impermeable or waterproof
substance, such as resin dissolved in spirits of wine or oil of turpentine,
and I recommend as being best adapted for the purposes of my Inven-
tion the composition known in commerce as gilders' lacquer, to which I
usually add to every three parts of the same one part of methylated
spirit for the purpose of making the lacquer to flow more freely and
evenly during the operation of coating. And in order to render the
composition softer I add Venice turpentine in the proportion of one-
sixteenth part of the whole. These proportions however may vary
according to the substance or quality of the lacquer and the quality
of paper used. The ingredients when mixed must be allowed to be
thoroughly dissolved and united before being used. This varnish must
be laid on the paper evenly, which can be most conveniently done by
means of a broad and soft brush, and I recommend that this operation
should be repeated twice or three times according to the consistency of
the varnish and the quality of the paper. The paper when so coated
must be thoroughly dry before being used. I recommend that sheets of
paper thus prepared should be kept ready for immediate use. I shall in
future. refer to the paper so prepared when describing my process as
"papyrographic paper."

page_text: In the next place upon the uncoated side of a sheet of papyrographic
paper prepared in the foregoing manner, and being perfectly dry, the
writing, drawing, or delincation of which fac-simile copies are intended
to be produced should be executed with an ordinary steel pen, using for
ink the liquid preparation hereafter described, and which writing must
be allowed to dry.
The liquid preparation I employ for executing such writing, drawing,
or delineation consists of a caustic preparation, such as water which has
been saturated with hydrate of sodium or hydrate of potassium, which
preparation may be colored with a suitable coloring matter, such as
Vandyke brown or other coloring matter capable of withstanding the
action of the alkali, and which matter will not neutralize the caustic
properties of the preparation. This preparation I shall in future when
describing my process allude to as the "papyrographic ink.
In the next place in order that the papyrographic paper which; has
been written, drawn, or delineated upon with the papyrographic ink may
be used for producing fac-simile copies it is necessary to remove those
parts of the varnish that have been acted upon or corroded by the action
of the said ink. This removal may be made in several ways, but I
recommend the following method, namely:-Upon a pad of textile
fabric, such as calico or linen that has been saturated with clean water,
the coated side of the written papyrographic paper is to be placed, and
is to be firmly and evenly pressed down, first covering it with a sheet of
blotting paper, the writing side being uppermost. The water from the
pad will within a few minutes commence to ooze through the lines of the
writing, drawing, or delineation, and the moisture appearing on the
uncoated surface should be immediately removed by means of the
blotting paper before alluded to in order to stay any lateral action of tho
papyrographic ink. This process should be continued until all the lines
of the writing are perfectly clear, which is a certain indication that the
ink has operated sufficiently. The papyrographic paper may now be
removed from the saturated pad, and any portions of corroded varnish
that still remain may be washed away with a soft brush.
I suggest that the position of the papyrographic paper be occasionally
changed while on the wet pad:
The effect produced by the washing before described is to remove
žuah nautirna of the vonnish as hava haon acted unan or corroded by the

page_text: action of the papyrographic ink along the lines of the writing, drawing,
or delineation which have been made.
It is next necessary to form a pad composed of a few sheets of
blotting paper, which must be cut slightly larger than the space
occupied by the writing, drawing, or delineation that has been executed
on the papyrographic paper, while it must be smaller than the area of
the said papyrographic paper, which must extend beyond the edges of
the pad. The pad must be then evenly moistened with a solution of
persalt of iron, and I recommend as best adapted for the purposes of my
Invention a solution of persulphate of iron, that is the liquor ferri
per sulphatis of the apothecary, hereafter called the "papyrographic pad
solution.
Having prepared the papyrographic paper, and executed the writing,
drawing, or delineation upon the uncoated side, and washed the same as
before described, and having prepared the papyrographic pad evenly
moistened with the papyrographic pad solution, it remains to prepare the
paper upon which the fac-simile copies are desired to be produced. For
this purpose any ordinary writing or printing paper is more or less
suitable if previously damped with a solution prepared as next described,
. and which I denominate the "papyrographic printing solution." This pre-
paration is composed of a saturated solution of ferrocyanide of potassium
or yellow prussiate of potash of commerce in the proportion of one part
of saturated solution of prussiate of potassium to eleven parts of water.
It is not however cssential that this exact proportion should be observed,
but I have in my experience found that a solution of this strength is
very suitable for my process.
. Having prepared the papyrographic pad the papyrographic paper
bearing the writing, drawing, or delincation desired to be copied, and the
paper damped with the papyrographic printing solution, the mode of
producing the fac-simile copies of the writing, drawing, or delineation
which has been executed upon the papyrographic paper is as follows:-
Place the papyrographic pad moistened or damped with the papyro-
graphic pad solution upon a perfectly flat surface, such as a piece of
pasteboard or wood, and flat upon the surface of the pad place the
papyrographic paper so that the uncoated side thereof upon which the
writing, drawing, or delineation has been executed may be next to the
pad and the coated or varnished side uppermost, and then if the papyro-

page_text: graphic paper be dry moisten it with clean water in order to give an
absorbing power to the exposed lines of the writing, drawing, or
delineation. Flat upon the surface of the papyrographic, paper put a
piece of dry blotting paper, and upon the top of the whole thus
arranged place another piece of pasteboard or perfectly flat piece of
wood or metal, and press the whole together in an ordinary letter-copying
press or some modification thereof. After a few seconds the exposed
lines of the drawing, writing, or delineation will be found impregnated
with the papyrographic pad solution. For the dry blotting paper
is then substituted a sheet of blotting paper damped in the papyro-
graphic printing solution, which upon being pressed against the
papyrographic paper in the manner herein-before described will be
found to bear in a blue color an exact fac-simile or copy of the
writing, drawing, or delineation made upon the papyrographic paper.
Care must be taken that the pressure is evenly distributed as far as
possible.
When a sheet of the paper to be printed upon already previously
damped with the papyrographic printing solution is substituted for the
damp blotting paper, upon being treated in a similar manner to that of
the blotting paper damped in the papyrographic solution before alluded
to, it will be found on taking it off that a fac-simile copy of the writing,
drawing, or delineation made upon the papyrographic paper has been
produced upon it in a blue color.
Without disturbing the arrangement of the pad and papyrographic
paper a fresh sheet of the paper to be printed upon can be placed upon
the papyrographic paper in the place of the sheet that has been printed,
and upon submitting it to pressure in the manner before described it
will be found that a second copy has been produced, and by continuing
the process a great number of copies can be successively obtained by
using other sheets of paper damped with the papyrographic printing
solution.
The action that ensues is as follows, that is to say, the solution of per-
sulphate of iron, called the papyrographic pad solution, with which-the
papyrographic pad is moistened being separated by the intervening.
sheet of papyrographic paper bearing the writing, drawing, or delineation.
to be copied from the solution of prussiate of potash, called the papyro-
graphic printing solution, with which the paper to be printed upon

page_text: is damped are able to come into chemical combination by means of
the pressure exerted by the press through the exposed parts of the
papyrographic paper along the lines of the writing, drawing, or
delineation where the papyrographic paper has been already acted
upon or corroded by the action of the papyrographic ink as before
desoxibed

page_text: I do claim is the producing copies or fac-similes of writings, drawings,
and delineations by chemical agency in manner herein-before described.
In witness whereof, I, the said Eugenio de Zuccato, have hereunto.
set my hand and seal, this Twenty-seventh day of March, in the
year of our Lord One thousand eight hundred and seventy-
four.
EUGENIO DE ZUCCATO. (L.S.)