An Improved Chemical Method of Producing Prints similar to Photographic Prints.
Year: 1897

page_text: Date of Application, 4th June, 1897
Complete Specification Left, 7th July, 1897--Accepted, 28th Aug., 1897
An Improved Chemical Method of Producing Prints similar to
Photographic Prints.
HENRY SOAR of 85 Grove Road Bow London Photographer and JOHN WOFFENDEN
COOPER of 85 Grove Road Bow London Photographers Assistant do hereby declare the
nature of this invention to be as follows:-
Heretofore in producing prints on paper coated with a metallic salt resource to the
action of light has invariably been the method of procedure. According to our
invention we obtain these prints by an entirely different method. A plate of metal
composed of Zinc bronze or other metallic substance is printed upon by any of the
usual photo engraving processes such as Albumen Gelatine Bitumen Fish Glue Greasy
Ink or Photogravure methods and carried to that point when it is ready to be etched..
The print in these cases being made from a transparency. Or a print can be formed
by any of the Bichromate processes transferred to glass or such like material made
humid and brushed over with bronze or other metallic powder or this powder is
incorporated with the film or a wash of soluble salt is given to that portion of the
plate which receives moisture or again a plate of metal may be coated with Bitumen,
Wax, Varnish or other resist and this cut through with a graver.
Further any
available method of forming a resist or stencil may be resorted to. A paper, fabric or
other support prepared by any of the ordinary methods of making material for
photographic or similar printing is taken, into which is incorporated a metallic salt.
The salt used is one having the property of being darkened by the metal from which
the plate has been made when the two cone into contact whilst humid. The support
holding this salt is damped placed upon the metallic plate and a print pulled by any
of the usual methods used in printing from block type or stone or can be squeegeed,
A chemical action is at once set up which in some instances we hasten by the
damping solution being composed of chemicals helping this reaction.
By these means a print is formed upon the paper or other support varying in color
according to the combination of the metals used. For example. We take a Zinc
plate prepare it by the Bitumen process of Photo engraving up to the point when it
is ready to be etched. Upon this a Gelatine coated paper holding Nitrate of Silver
(prepared in the usual manner of making Gelatine Chloride Silver paper,) is placed
which had been previously made moist by floating upon water. On pulling this
proof by squeegeeing it into contact we have a print identical in color to a gold
toned proof made by the usual exposure to light. It now only remains to fix out
the salts unacted upon to complete the operation although many modifications can
be resorted to in the combination of chemicals to give tone density and results more
permanent.
1000

page_text: An Improved Chemical Method of Producing Prints similar to
Photographic Prints.
HENRY SOAR 85 Grove Road, Bow, London Photographer and JOHN WOFFENDEN
COOPER 85 Grove Road, Bow, London Photographers Assistant do hereby declare
the nature of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
Heretofore in producing photographic prints upon paper or other support coated
with a metallic salt resource to the action of light has invariably been the method of
procedure.
According to this invention we obtain similar prints by an entirely different
method.
The property possessed by various metals to darken other bodies of a metallic
nature by deposition when brought into chemical union has suggested a means of
forming such prints.
In this process the printing surface like lithography to which it is somewhat
analogous is formed flat or but slightly recessed. Part is bare metal-or with but a
slight pervious covering as thin porous gelatine-to form chemical attraction with
metallic salts held in or on a support such as paper.
Part is covered with an
impervious resist of varnish, hardened gelatine or other substance which prevents
chemical combination between the metallic bodies.
The first stage is to obtain such a plate of the matter to be reproduced which can
be either of a sketch writing drawing photograph type or other print separate or
coinbined.
By one or other of the photo-engraving lithographic or appertinent methods a
print is made to form a protecting surface corresponding to the whites of the picture
which we are reproducing on a metal plate such as zinc or copper in lime stipple
halftone screen or for intaglio etching. It being only necessary for our purpose to
carry the process to the point when the plate is prepared ready for the etching bath.
The print being inade from a positive or transparency of the original matter as in
photogravure thus leaving bare only such part of the metal which for a type block
etching process would be covered with a resist enabling the necessary reaction to be
set up when brought into contact with the metallic salts. Obvious means can be a
resorted to allowing such a print from a negative or for a transfer to be used.
resist likewise is obtained by drawing with a gelatinous substance or by making a
print by Bichromate or kindred printing processes either upon glass or such like
support or one is transferred to a substance of an impervious but not of a metallic
nature. The non-metallic material is the resist, the print whilst damp being then a
dusted over with bronze or other suitable metallic powder to form the affinity or a
solution of metallic salt or salts is applied to it or a metal in a fine state of powder
incorporated with the substance composing the print or the drawing where available.
The metals used being such as those mentioned in the context.
A
12.
Further we engrave or otherwise cut through a resist coated upon a metal plate or 4
use ordinary metal type or type blocks for the printing surface. Any known process
of making or obtaining such a plate as here shewn can be utilized according to the
convenience of the method to the results required.
1.
Our next proceeding is to incorporate in or upon one or both sides of a suitable
paper fabric or other support as for instance the ordinary photographic papers a 4
metallic salt. This we do by any of the usual means employed for coating such
papers or other supports.
The salts used are those having the property of forming a colored deposit when

page_text: brought into chemical affinity with the metal of the aforementioned plate-such as
silver nitrate. A support holding such salt and prepared similar to the photographic
silver printing papers upon the market can be used the general formulae of which
are well known. We prefer however to adopt one containing gelatine into which the
salt or salts are incorporated in the manner of making emulsions for Gelatino printing
out paper.
For guidance we give the following formula which forms prints
resembling the ordinary ones obtained by exposure to daylight,-Gelatine from
20 grains silver nitrate from 10 grains water one ounce with or without citric acid
from 10 grains to be used if the paper is to be kept. To which may be added either
to the emulsion or the damping water as described later such salts as Gold Chloride
from one grain or Ammon. citrate of Iron from 15 grains to the ounce of water.
Although most of the prepared printing papers used in photographic printing are
available without any or with but slight modifications.
The support holding the salt or salts is damped by floating upon a bath containing
water or by other convenient means and placed upon the plate or otherwise brought
into contact with it. Pressure being obtained either by hand or mechanically. The
act of union between the chemicals brought into combination causes by substitution
and reduction a colored metalline deposit to form upon the surface of the support
wherever the two come into chemical contact thus forming the desired print.
These combinations can be varied by adding other salts to the emulsion containing
the silver nitrate or its equivalent or to the damping fluid such as the chlorides of
Gold and platinum or salts of the common metals can be added as Ammon. citrate
of Iron ut supra which alter the composition and color of the deposited print. Other
changes occur by varying the metal of the plate employed, Lead Iron Nickel and
other metallic substances besides those previously mentioned being available.
Nothing now remains but to fix out the salts unacted upon by the usual methods
and wash the support. At this stage further combinations altering the tone are to
be obtained by brushing or otherwise bringing into chemical attraction with the
deposited metallic print solutions of salts of metals such as those before noted which
have the power of uniting with the original deposit.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is :-
A method of producing prints which consists of bringing into affinity a suitably
prepared metallic plate such as is herein described and a damped support holding a
salt such as silver nitrate or combined with other salt or salts whereby a colored
metalline deposit is chemically formed on such support wherever chemical contact
is allowed to occur between the metal of the plate and that contained on the
support.