IMPROVE- MENTS IN PHOTO-MECHANICAL PRINTING
Year: 1870

page_text: LETTERS PATENT to Ernest Edwards, of 6, Lincoln Terrace, Willesden
Lane, in the County of Middlesex, for the Invention of "IMPROVE-
MENTS IN PHOTO-MECHANICAL PRINTING."
Sealed the 10th March 1871, and dated the 15th September 1870.
PROVISIONAL SPECIFICATION left by the said Ernest Edwards at the
Office of the Commissioners of Patents, with his Petition, on the
15th September 1870.
I, ERNEST EDWARDS, of 6, Lincoln Terrace, Willesden Lane, in the
County of Middlesex, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN PHOTO-MECHANICAL PRINTING," to be as follows:-
In my previous Patent No. 3543, dated the 8th December 1869, I have
described various improved methods of photo-mechanical printing. This
Invention relates to further improvements in carrying out the same
methods, to improvements in other methods, and to new methods of
photo-mechanical printing.
In carrying my Invention into effect I proceed as follows:-After
the surface which is to receive the gelatine or analagous film has been

page_text: cleaned, it is to be rubbed over with a solution of wax or other suitable
substance, or to be coated with collodion or a solution of india-rubber,
or to be treated with any of the known methods which will allow of the
removal of the gelatine film after the latter has become dry. The pre-
paration of the film is then to be proceeded with by any of the known
methods or by any of the methods detailed herein; after the film has
become dry it is to be removed from the glass and the insolation by light
may be effected on either of its surfaces. After insolation the film is to
bc cemented to the surface on which it is to remain during printing at
the press. A solution of Canada balsam in chloroform may be used as
the cement, or india-rubber or collodion or any of the ordinary cements
or varnishes. No cement at all is necessary provided all air is got rid of
between the film and its support. Glycerine, sugar, castor oil, or other
suitable oil may be added to give flexibility to the film. And it is to be
understood that the removal of the film and its subsequent replacement
may be effected at any convenient stage of the operations.
Another improvement consists in using plates of soft metal or other
material as the basis for the printing film. The printing block (by which
I mean the plate and the film of gelatine or analogous substance thereon)
is after insolation and washing to be submitted to pressure, so that the
printing surface may be level when the inking rollers and pressure are
applied; or to produce the same result the inequalities of the surface may
be filled up with insoluble gelatine or other suitable substance. Where
non-reversed pictures are desired I allow the light to act completely
through the gelatine or other film, which must be stripped from its
support either before or after exposure and inked on the reverse side to
that which has been in contact with the negative; or I obtain a print
in gelatine or other analagous substance and transfer this for develope-
ment to the surface of a film of gelatine which has been rendered partly
or entirely insoluble. The surplus gelatine is then washed away with
hot water. After drying the plate is to be sufficiently damped and put
in the press for printing.
may or
I also prepare plates for printing from by the following method:-I
prepare a film of gelatine or other analogous substance, which
may not be first rendered insoluble, and treat it with perchloride of
iron and tartaric acid, or otherwise treat it so that it shall be non-
absorbment until acted upon by light. After insolation those parts where
light has acted are rendered again absorbent. Transparent positives are

page_text: necessary for printing by this method, which, therefore, admits of
reversed or non-reversed and enlarged or reduced pictures being pro-
duced.
Another improvement consists in using (instead of greasy ink) powder
colors, which may be dusted over the plate after insolation by light
and damping, these adhere in inverse proportion as light has acted. The
picture thus obtained may be transferred on to the surface of suitably
prepared paper and the operation repeated; or water colors may be used.
Sometimes also I take a plate of lithographic stone, slate, or other
suitable porous material, and this having been first thoroughly dried is
allowed to absorb a solution of gum, albumen, gelatine, or other suitable
substance, which may or may not have been previously rendered in-
soluble by alum or other means. This plate is to be rendered sensitive
to light either during its preparation or subsequently. After exposure
and printing the plate is to be printed from as usual, or the reverse
method described above may be adopted.
Another method is to cause a suitably porous material to absorb a
solution of bitumen or other analagous substance. After insolation
those parts not acted on by light are washed away by turpentine, benzole,
or a suitable solvent, and the plate is then ready for printing.
Where photographs are desired to be placed on blocks used for wood
or other cutting, I produce a print on paper in a suitable ink and
transfer it by pressure to the blocks, or I place the block itself in
contact with the inked gelatine matrix. The printing films may also
be transferred to cylinders, and they may then be printed in cylinder
printing machines.
It is to be understood that all these modifications are intended to be
applied both to gelatine and analogous films rendered partly or com-
pletely insoluble, and to films that have not been so treated.
It is also to be understood that by gelatine and similar organic
substances is meant all those substances which have the same or similar
actions and reactions in relation to the effect of light upon them.
In printing any paper may be used, but I prefer to use either an
enamelled paper or one that has been very heavily rolled. After printing
the prints may be coated with collodion or varnish or other suitable
preservative, or be enamelled in any of the ordinary ways.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Ernest Edwards in the Great Seal Patent Office on
the 15th March 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ERNEST
EDWARDS, of 6, Lincoln Terrace, Willesden Lane, in the County of
Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date, the Fifteenth day of September, in the year
of our Lord One thousand eight hundred and seventy, in the thirty-`
fifth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Ernest Edwards, Her special licence that I,
the said Ernest Edwards, my executors, administrators, and assigns, or
such-others-as-I, the said Ernest Edwards, my executors, admiñis-
trators, and assigns, should at any time agree with, and no others, from
time to time and at all times thereafter during the term therein ex-
pressed, 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 PHOTO-MECHANICAL
PRINTING," upon the condition (amongst others) that I, the said Ernest
Edwards, 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 Ernest Edwards, 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:—
This Invention relates to the method of printing which is, based on
the principle that when a suitable surface is coated with bichromated
gelatine and an image obtained on it by light the parts so acted on by
light refuse to absorb water, but take greasy ink; those that have not
been acted on by light and remain unaltered absorb water and refuse
the ink; and those that have been partly acted on by light partly absorb
the water and partly refuse the ink.

page_text: In my previous Patent, dated 8th December 1869, No. 3513, I have
described various improved methods of pho-mechanical printing.
This Invention relates to further improvements in carrying out the
same methods, to improvements in other methods, and to new methods
of photo-mechanical printing, and consists,
First. Of methods of removing the printing films from the surfaces
on which they have been prepared to those on which they are to be placed
during printing at the printing press.
Second. Of methods of obtaining level or flat surfaces in the printing
films.
Third. Of improvements in the methods of printing from such films.
Fourth. Of methods of obtaining either reversed or non-reversed
printing films from ordinary negatives.
Fifth. Of methods of preparing lithographic and artificial stones for
printing.
Sixth. Of methods of preparing transfers for placing on blocks for
wood cutting, lithography, engraving, and other purposes, and of printing
directly on blocks for the same and other purposes.
In carrying these my improvements into effect I proceed as follows:
First. After the level surface, such as that of metal, wood, stone,
glass, porcelain, slate, enamel, collodion, ebonite, which is to receive the
gelatine or analogous film has been cleaned, it is to be rubbed over
with a solution of wax, or coated with collodion or india-rubber, or
treated by any of the known methods which will allow of the removal of
the gelatine film after the latter has become dry. The preparation of
the printing film (by which I mean that film which is to be used in the
press for printing from) is then to be proceeded with by any of the
known methods or by any of the methods herein-after detailed. After
the printing film has become dry it may be removed from the surface on
which it has been prepared. The insolation or exposure to light for the
purpose of forming a picture may be effected on either of its surfaces,
and the film is then to be attached to the support on which it is to
remain during printing at the press. This support may be of such a
substance as metal, glass, porcelain, enamel, ebonite, collodion, and the
printing film is attached to such support by placing the two surfaces
(viz., the upper surface of the support and the under surface of the
priuting film) in contact under water, quickly withdrawing them there,

page_text: from, and getting rid of superfluous water by pressure. To ensure
greater adhesion the surface of the support may be coated with Canada
balsam, collodion, india-rubber, gelatine, gelatine rendered wholly or
partly insoluble, or albumen, or any of the ordinary cements or varnishes.
Glycerine, sugar, castor oil, or other non-drying oil may be added to give
flexibility to the film, and it is to be understood that the removal of the
film and its subsequent replacement may be effected at any convenient
stage of the operations, either before or after exposure to light. Attach-
ment of the surfaces of the film and of the support may also be obtained
by coating each with such a material as india-rubber, and making them
adhere together by heavy pressure, such as that obtained in a copper-
The following is a convenient method of working; but I wish it to
be understood that I do not confine myself to the particular formulas
given, nor to the relative proportions of the several constituent parts of
the substances given in such formulas, but I vary the component parts
and the relative proportions of such component parts as may be found
advisable in various circumstances. The surface of a piece of fincly
ground plate glass of sufficient thickness is rubbed over with a solution
of wax in ether. After rubbing off again as much as is possible of this
solution so as to leave an imperceptibly fine coating of wax the plate is
made perfectly level. A solution of one ounce of gelatine, five grains of
chrome alum, and half a drachm of bichromate of potash is to be made
in twelve ounces of water at a temperature of about 100° Fahrenheit,
and poured over the plate in the proportion of the above quantity to one
square foot of surface of the plate. After the gelatine has set I cause it
to be dried at a temperature of 70° to 75° Fahrenheit. When perfectly
dry it is stripped from the glass, placed in a damp place still limp, and is
then printed on by exposure to light under a negative in the usual way.
The printing is complete as soon as the details of the image appear, and
the back of the film is then exposed to light (except an edge all round
about half an inch) till the color of it is about twice as deep as before
exposure; it is then to be placed under water in contact with a polished
pewter plate (which has been coated with a solution of india-rubber) and
quickly withdrawn; the two surfaces are pressed in contact, superfluous
water is got rid of by the use of a squeegee," and a thin coating of
india-rubber is put round the edge of the film by means of a camel's
hair brush dipped in a solution of that material; when this is dry the
66

page_text: .
plate is steeped in water till the superfluous bichromate is soaked out of
the film, which is then ready for printing at the press. It is, of course,
necessary that all the operations up to this stage (whilst the film is dry),
with the exception of the exposure to light under the negative, should
be conducted in a non-actinic light. Should the printing film not be
required immediately it may be dried, and when dry removed from its
support and stored away for future use, when it is laid down on the plate
in precisely the same way as that just described. Where convenient an
intermediate film of gelatine may be placed between the supporting
plate and the printing film, and with this intermediate film a white
pigment may be mixed, or a white pigment may be mixed with the
printing film itself. In the case of a black support, such as ebonite or
vulcanite, being used, this allows the progress of the inking operation to
be inspected. Where it is desirable to obtain a grain on the prints that
surface of the printing film which has been in contact with the ground
glass should be placed next to the negative. Or any desired grain may
be produced by the use of other suitable surfaces instead of that of ground
glass.
Second. When it is desired that the printing surface should be level
or less in relief than is ordinarily the case, a plate of soft metal, such
as lead or type metal, is used as the support for the printing film, and
heavy pressure is applied, so that the gelatine film is imbedded into its
surface. Or a level surface, such as that of glass, is coated with wax
or collodion or india-rubber, or any of the before-mentioned substances.
The printing film after exposure to light is attached to this surface with
the exposed face downwards by means of water and the "squeegee," or
by any of the well-known means, or by any of the means indicated
herein. It is then to be swollen by allowing it to absorb water, and
when in relief it is to be backed up and prepared with plaster of Paris,
cement, or by any of the known means in use for the preparation of
clectrotype plates for printing.
Third. In the printing of proofs I obtain greater intensity of the
shadows, where this is desirable, by dusting over them, after printing,
powder colors, such as are used in lithography. And it is to be under-
stood that all the means available in lithography for producing various
effects are also available in this process. Sometimes also where great
intensity is desired I use the copper plate method of inking with a dabber.
The dabber being charged with ink is worked over the plate in the usual

page_text: way, the surplus ink is cleared off the plate with a roller, and the
impression is pulled in the usual way. I also avail myself of the method
adopted in wood, block, and type printing for obtaining greater or less
local intensity by what is technically known as overlaying. In pro-
ducing pictures for enamelling and burning in I sometimes increase
their intensity by the use of the same method of inking as for copper-
plate, and on to the paint thus obtained I dust suitable enamel colors.
It is to be understood that the printing of the proof may be effected not
on paper only, but on any surface on which it is customary or possible
to obtain prints by any of the printing methods in common use. In
printing any paper may be used, but I prefer an enamel paper or one
that has been heavily_rolled_or_burnished. After-printing-the-prints-
may be coated with collodion or varnish, or be enamelled in any of the
ordinary ways. Where prints are required with margins so as not to
require subsequent mounting, I sometimes also use a mask made of very
thin metal, having an opening the size of the finished print; this mask
is laid on the plate, and the paper on which the impression is to be
made is laid over it. I use such metal masks in the same way as and
instead of the paper ones described in the Specification of my Patent
of December 8th, 1869, No. 3543. The printing films may also be
transferred to cylinders, and may then be printed in cylinder printing

page_text: portion of about three parts of the former to one of the latter in one
hundred of water. After insolation those parts that have been acted
on by light become again absorbent, but the washing and printing of
the proofs must be conducted in a place from which actinic light has
been excluded, or the continued action of such light would render the
whole film again absorbent. Transparent positives are necessary for
printing by this method, which tlierefore admits of reversed or non-
reversed and enlarged or reduced pictures being produced.
Fifth. Where it is convenient to use a lithographic or porous stone or
slate such material is first thoroughly dried, and is then immersed in a
solution of gum, albumen, or gelatine, with bichromate of potash or
other known sensitizing material, and alum or other known substance
capable of rendering the gum, albumen, or gelatine partly or com-
pletely insoluble on the latter becoming dry. Sixteen parts gum, one
part bichromate of potash, one-tenth of a part chrome alum, one
hundred parts water is a convenient formula for this purpose. The
stone having absorbed as much of this solution as it will retain is to be
dried, and after insolation by light and washing is to be printed from in
the ordinary way. Or a printing block may be formed by the admixture
of such substances as plaster of Paris, Portland cement, artificial stone,
with gelatine and a bichromate, with or without the addition of any
of those substances which produce or tend to produce insolubility of
gelatine. Sixteen parts gelatine, one part bichromate of potash, two
hundred parts water, with plaster of Paris sufficient to make a firm mass
may be used.
When dry the insolation, washing, and printing are to
be proceeded with in the ordinary way; or the reversed methods
described above may be adopted.
Sixth. Where it is desired I produce prints in transfer ink on transfer
paper from the printing films, and I transfer these prints to the surface
either of wood blocks for wood cutting, of stones and zinc for lithography
or zincography, or of stone, copper, steel, zinc, for engraving, and to
such surfaces as wood or metal for ornament; and I use them for all
purposes where transfer prints are ordinarily used; or I place the plates
on which the transfers are to be made themselves in contact with the
printing film.
In the foregoing descriptions I wish it to be understood that by
gelatine all those substances are meant which are well known to -have

page_text: the same or similar actions and reactions in relation to the effect of
light upon them.
And it is further to be understood that the modifications and improve-
ments described are intended to be applied both to gelatine and analogous
films so treated as to be partly or completely insoluble, and also to
films that have not been so treated.
In witness whereof, I, the said Ernest Edwards, have hereunto
set my hand and seal, this Fifteenth day of March, in the year
of our Lord One thousand eight hundred and seventy-one.