A New Process for Producing Glass Printing Plates.
Year: 1891

page_text: Date of Application, 26th May, 1891
Complete Specification Left, 25th Feb.. 1892-Accepted, 26th Mar., 1892
PROVISIONAL SPECIFICATION.
A New Process for Producing Glass Printing Plates.
I, FREDERICK WINTERHOFF of 3 Ashmount Road in the Parish of Tottenham,
London, N. Lithographer and Glass Embosser, do hereby declare the nature of
this invention to be as follows :-
Heretofore, lithographic-stones, zink-plates, woodcuts, or printing plates produced
by photo-lithography, were used as printing plates, all these are very costly and
require experienced workmen, and great expenses, for handling and space, especially
the printing from lithographic-stones.
Glass printing plates are very cheap, and can be transfered from, by any ordinary
workman, who knows nothing about printing at all, after he has seen it once.
The space these plates require, is very little, as fifty glass printing plates, will not
take up the space one lithographic-stone does, and the same can be produced to
any size on any sheet or plate glass, I produce them on ordinary 21 oz. window
glass.
labour.
By my invention I am able to greatly decrease the cost of printing plates and
As this invention has for its object, the means of producing glass printing
plates, for transfering onto lithographic-stones, zink, or any other plate, which is
used for printing, or to print any number of copies from the glass plates direct.
I clean my glass plate, well, and then coate the same with a solution of gelatine,
Syrian asphalte, and such substances, which will be affected by the light, and let
the same dry.
When dry, either transfer or print direct on this coated surface, from any
printing plate and use any ordinary paper for transfering.
I then place the plate with the coated side towards the light, for half an hour,
the result being, that the exposed surface of the coating is hardened, but the portion
covered with the printing ink, being protected from the action of the light remains
I then wash the protected parts out with mineral oil.
soft.
Then the glass plate is put under fluoric-acid for about half an hour, I then wash
the same well with water and clean it, whereupon it is ready for printing from.
Dated May 26th 1891.
FREDK. WINTERHOFF.
COMPLETE SPECIFICATION.
A New Process for Producing Glass Printing Plates.
1, FREDERICK WINTERHOFF of 3 Ashmount Road in the Parish of Tottenham,
London, N., Lithographer and Glass Embosser, 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, lithographic stones, zink-plates, woodcuts, or printing plates produced
by photo-lithography, were used as printing plates, all these are very expensive and
require experienced workmen and great expenses for handling and space especially
the printing from lithographic stones.
Glass printing plates are very cheap and can be transfered from by any ordinary
workman, who knows nothing about printing at all, after he has seen it once.
The space these plates require is very little, as fifty glass printing plates will not
take up the space one lithographic stone does, and the same can be produced to

page_text: any size, on sheet or plate glass, I produce these printing plates on ordinary 21 oz.
window glass.
By my invention, I am able to greatly decrease the cost of printing plates and
labour, as this invention has for its object the means of producing glass printing
plates for transfering onto lithographic stones, zinc or any other plate which is used
for printing, or to print any number of copies from the glass plates direct.
I clean my glass plate well and then coate the same with a solution of gelatine,
Syrian asphalte and such substances which will be affected by the light and let
same dry.
I prefer to use a solution made in the following manner.
I take about 25 lbs. of best Syrian asphalte and add to this about one gallon
and a half of turpentine, and boil this in a sand bath, to about the consistency of
treacle, for about 4 to 5 hours, and when boiled as required I fill this solution in tin
cans and let same stand until wanted for usc.
With this asphalte solution I coate the glass and let same dry in any room
without darkening same. When dry I either transfer, print direct or draw on this
coated surface, and for transfering or printing use any printing plate and any
ordinary paper for transfering or I prefer to prepare a paper in the following
manner.
I take about 50 sheets of a soft sized paper size about 32 × 42 inch, and coate
the same with the following mixture.
I take about 4 ounces of pure corn starch, and boil same in the usual manner, I
then mix with this starch about one pound of best glycerine and about half a pound
of dissolved gum arabic of the best quality.
With this coate the soft sized paper very evenly and hang same up to dry.
For instance supposing I require a wall poster say 40 x 30 inches, stones of this
size are not over plentiful in many offices, 1 draw my design on four small stones in
sections and stick same together and transfer same onto a sheet of common window
glass, the transfering being performed in the following manner, I place my print or
transfer onto the coated surface of the glass and let same pass between the rollers
of a mangle, the rollers of said mangle being composed of india rubber, instead of
wood as in the ordinary mangles.
When thus transfered I place the plate with the coated side towards the light for
half an hour, the result being that the exposed surface is hardened, but the portion
covered with the printing ink, being protected from the action of the light remains
soft, then wash the protected parts out with mineral oil.
I then place the glass plate under fluoric-acid for about half an hour, I then
wash the same well with water and clean it, whereupon it is ready for printing from,
and it must be understood that these printing plates can be made to any required,
size.
To produce the drawing or design back onto a litho-stone, to print white on
black ground, I simply take a transfer on the herein mentioned transfer paper and
transfer the same onto the stone in the usual manner, but to produce the design or
drawing from the glass printing plate, black on white ground, I proceed in the
following manner, I first polish the stone as for litho-drawing, and when properly
dry, so that there is no dampness in the stone, I dissolve some litho-writing-ink and
cover the stone all over with the same, and let stand to dry for an hour or two, when,
dry I wash the ink all off with turpentine, so that the stone is quite free from ink,
and coate the same over with a solution of the asphalte and let dry, when dry I
take a transfer from the glass plate, and transfer the same on the coated surface of
the stone in any litho-press, when transfered, I expose same to the light for
half an hour, and then wash out as before, and it will be found that the design or
drawing is black on white ground, on the stone, as same was originally drawn by
the artist.
I then acid this drawing with very strong acid, as used in the litho-trade and gum
the stone over, when same is ready for printing from.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
Firstly) The process or combination of processes herein described.
Secondly) The producing and using of glass printing plates for lithographic and
other purposes.
Thirdly) The coated paper as described, and
Fourthly) The covering and protecting of such places on the coated surface by
transfering, direct printing or drawing.
Dated this 25th day of February 1892.
FREDRICK WINTERHOFF.