AN IMPROVEMENT OR IM- PROVEMENTS IN THE PRODUCTION OF PRINTING SURFACES
Year: 1878

page_text: LETTERS PATENT to Alfred Pumphrey, of Birmingham, in the County_of
Warwick, Manufacturer, for the Invention of "AN IMPROVEMENT OR IM-
PROVEMENTS IN THE PRODUCTION OF PRINTING SURFACES."
Sealed the 19th July 1878, and dated the 8th February 1878.
PROVISIONAL SPECIFICATION left by the said Alfred Pumphrey at the
Office of the Commissioners of Patents on the 8th February 1878.
to
ALFRED PUMPHREY, of Birmingham, in the County of Warwick, Manufac-
turer. AN IMPROVEMENT OR IMPROVEMENTS IN THE PRODUCTION OF PRINTING
SURFACES."
My said Invention consists of the process or combination of processes herein-after
described whereby printing surfaces can be produced from writings or drawings
written or drawn with ordinary writing ink on paper.
In preparing the said printing surfaces I proceed as follows:-I take a flat plate
of glass, slate, metal, or other hard substance, or a flexible material, such as paper or
cloth, and coat it with a thin film of gelatine. This may either be effected by
making a solution of gelatine in hot water or by making a solution of gelatine by
the aid of acetic acid, as is well understood. By the use of either of these solutions
poured on the plate I obtain a film of gelatine of about one hundredth of an inch in
thickness. Plates so prepared when dried may be kept any length of time before
being further treated.
When it is wished to make a printing surface from one of the prepared plates the
prepared plate is plunged in or well wetted with an aqueous solution of bichromate
of potash containing about one per cent. of the said bichromate of potash.. After the
plate has been exposed to the action of this solution during about ten minutes, it is
removed from the solution and the surplus solution attached to it is absorbed by
blotting paper or otherwise.
The writing or drawing, made with common writing ink on paper (the said
writing or drawing being quite dry) is now placed face downwards upon the
plate in the state of preparation last described, and the prepared plate and writing

page_text: or drawing thus in contact are passed between a pair of rolls, or pressed in a
copying press, or otherwise strongly pressed together. By the action of the ink
upon those parts of the plate it has come in contact with, the bichromatised gelatine
on those parts has been made insoluble, and on removing the paper from the pre-
pared plate the said plate may be used as a printing surface.
By applying printing ink to the said plate, and otherwise proceeding as in
printing from lithographic stone, impressions in printing ink may be obtained from
the plate, the said impressions being fac simile reproductions of the writing or
drawing which had been pressed into close contact with the prepared plate.
The writing ink with which the writing or drawing is executed should be
ordinary writing ink, that is, writing ink containing a salt of the protoxide of iron.
It is by the action of the said salt of iron on the gelatine that the latter is rendered
insoluble, and is thereby enabled to receive the printing ink when the printing roller
is passed over the plate, the other parts of the gelatine film still remaining soluble
will not take ink from the printing roller.
In order the more effectually to secure the adhesion of the film of gelatine to the
plate the said plate may be coated with a thin coating of albumen before the solution
of gelatine is applied. The solution of albumen should have a small quantity of
bichromate of potash added to it when the plate is to be prepared with gelatine to
which acetic acid has not been added, but the addition of bichromate of potash to
the albumen is unnecessary when the solution of gelatine employed contains acetic
acid, o 91.
I
Although I prefer the use of ordinary writing ink in carrying my Invention into
effect, yet other black or colored aqueous solutions may be employed, provided the
said solutions contain photosulphate of iron, alum, or gallic acid, or any of the sub-
stances which produce insolubility in gelatine.
Before taking impressions from the printing surface prepared, as herein-before
'described, the said surface may be advantageously washed in water for the purpose
of removing the undecomposed bichromate of potash from the film of gelatine.
When the plates are to be used in hot weather, or when the gelatine employed is
not sufficiently hard, the required condition of the gelatine may be obtained not
only by the addition of acetic acid, but also by the use of gum resins, or chrome, or
other alum.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alfred Pumphrey in the Great Seal Patent Office on the 1st.
August 1878.
ALFRED PUMPHREY, of Birmingham, in the County of Warwick, Manu-
facturer. "AN IMPROVEMENT OR IMPROVEMENTS IN THE PRODUCTION OF PRINTING.
SURFACES."
My said Invention consists of the process or combination of processes, herein-after*
described, whereby printing surfaces can be produced from writings or drawings
written or drawn with ordinary ink on paper.
In preparing the said printing surfaces I proceed as follows:-I take a flat plate
of glass, slate, metal, or other hard substance, or a flexible material, such as paper or
cloth, and coat it with a thin film of gelatine. This may either be effected by
making a solution of gelatine in hot water, or by making a solution of gelatine by
the aid of acetic acid, as is well understood. By the use of either of these solutions
poured on the plate I obtain a film of gelatine of about one-hundredth of an inch in
thickness. Plates so prepared when dried may be kept any length of time before
being further treated.
When it is wished to make a printing surface from one of the prepared plates the
prepared plate is plunged in or well wetted with an aqueous solution of bichromate
of potash containing about one per cent. of the said bichromate of potash. After the
plate has been exposed to the action of this solution during about ten minutes it is.
removed from the solution, and the surplus solution attached to it is absorbed by
blotting paper or otherwise.
The writing or drawing, made with common writing ink on paper (the said.
writing or drawing being quite dry), is now placed face downwards upon the moist
plate in the state of preparation last described, and the prepared plate and the
writing or drawing thus in contact are passed between a pair of rolls, or pressed in
a copying press, or otherwise pressed together. By the action of the ink
upon those
parts of the moist plate it has come in contact with, the bichromatised gelatine on
those parts has been hardened, contracted, and made impermeable to moisture, and
on removing the paper from the prepared plate the said plate may be used as a
printing surface.
By applying printing ink to the said plate, and otherwise proceeding as in
printing from lithographic stone, impressions in printing ink may be obtained from
the plate, the said impressions being fac simile reproductions of the writing or
drawing which had been pressed into close contact with the prepared plate.
The writing ink with which the writing or drawing is executed should be
ordinary writing ink, that is, writing ink containing a salt of the protoxide of iron.
It is by the action of the said salt of iron on the bichromated gelatine that the latter
is rendered impermeable to moisture, and is thereby enabled to receive the printing
ink when the printing roller is passed over the plate, the other parts of the gelatine
film still remaining permeable by and retaining moisture will not take ink from the
printing roller.
In order the more effectually to secure the adhesion of the film of gelatine to the
plate, the said plate may be coated with a thin coating of albumen before the solution
of gelatine is applied. The solution of albumen should have a small quantity of
bichromate of potash added to it when the plate is to be prepared with gelatine to
which acetic acid has not been added, but the addition of bichromate of potash to the
albumen is unnecessary when the solution of gelatine employed contains acetic
acid.
Although I prefer the use of ordinary writing ink in carrying my Invention into
effect, yet other black or coloured aqueous solutions may be employed provided the
said solutions contain photosulphate of iron, alum, or gallic acid, or any of the sub-
stances which produce contraction or impermeability in gelatine; or a solid ink
may be employed instead of a liquid ink, as herein-after moré fully explained.

page_text: When the plates are to be used in hot weather, or when the gelatine employed is
not sufficiently hard, the required condition of the gelatine may be obtained, not
only by the addition of acetic acid, but also by the use of gum resins, or chrome, or
other alum.
I will now proceed to describe in detail the composition of the solutions which I
employ in carrying my Invention into effect; I wish it however to be understood
that I do not limit myself to the particular proportions of the materials herein-after
given, as the proportions may be varied within considerable limits, but the propor-
tions herein-after given I have found to answer well in practice, and are the best
with which I am acquainted.
For the first coating of the plate or surface I employ a solution consisting of :—
Albumen (white of egg) One part by weight.
Gelatine solution
One
"
"
The said gelatine solution is made by dissolving one part by weight of gelatine,
and half a part by weight of bichromate of potash in thirty parts by weight of
The plates having been coated with the solution are exposed to the light
until the film has hardened.
water.
For the second coating I employ a solution having the following composition:—
Two parts by weight.
Gelatine
Water
Acetic acid
Chrome alum
Alcholic solution
-
-
Eight
Three "
27
"
"
"
"
1/2 part (one thirty-second part.)
One and half parts by weight
gum benzoin.
The alcholic solution of gum benzoin is made by dissolving one part by weight of
gum benzoin in five parts by weight of alcohol.
The quantity of the second solution which I have found most suitable is two
ounces of the said solution to each square foot of the plate or surface to be coated.
The second coating of the plates is dried slowly. In summer they dry sponta-
neously in from 24 to 36 hours, but in winter I prefer to dry them in an artifically-
warmed chamber, as the drying should be effected at a temperature not lower than.
60 degrees of Fahrenheit's thermometer.
The solution of bichromate of potash into which the prepared plate is dipped in
order to prepare a printing surface thereform is composed of one part by weight of
bichromate of potash, to one hundred parts by weight of water. I prefer to keep
the plate immersed in the solution not less than five minutes. It may however
remain in the solution longer without injury.
The ink with which the writing or design is to be executed is made by the
addition of one part of weight of protosulphate of iron to eight parts by weight
of common ink. Or the aniline inks now in common use may be employed
with like effect by adding a similar proportion of protophate of iron to the
ink. Where it is preferred or is desirable to produce the writing or design
by the use of a solid ink employed as crayons are employed, instead of making the
writing or design by the use of liquid ink applied by a pen or brush I employ a
solid ink or crayon made of one part by weight of carbon or vegetable black and
one part by weight of protosulphate of iron mixed with sufficient solution of gum
arabic to bind the materials together by being subjected to pressure,
My Invention may be modified by adding the chromate of potash to the ink and
the solution of protosulphate of iron to the plate or surface, but I prefer the method
of carrying my Invention into effect herein-before described.
Although I prefer to employ protosulphate of iron to produce the required imper-
meability in the gelatine, yet alum, or gallic acid, or other substances known to
produce contraction and impermeability in gelatine may be employed. But as the
use of protosulphate of iron produces the best results I do not think it necessary to
describe in detail the manner of producing inferior results.
Having now described the nature of my Invention and the manner in which
the same is to be performed, I wish it to be understood that I claim as my Inven-
tion of an improvement or improvements in the production of printing surfaces

page_text: producing a printing surface by pressing upon a surface of moist gelatine containing
bichromate of potash, a writing or design executed in liquid or solid ink containing
protosulphate of iron or other chemical capable of producing contraction or imper-
meability in moist gelatine impregnated with bichromate of potash, substantially as
herein-before described.
In witness whereof, I, the said Alfred Pumphrey, have hereunto set my
hand and seal, this Thirtieth day of July, in the year of our Lord One
thousand eight hundred and seventy-eight.
Witness,
THOMAS JONES,
Compton House,
Barmouth.
ALFRED PUMPHREY. (L.S.)