Improvements in Preparing the Surface of Zinc Plates for Lithographic Purposes.
Year: 1889

page_text: Date of Application, 31st July, 1889
Complete Specification Left, 20th Mar., 1890-Accepted, 19th Apr., 1890
PROVISIONAL SPECIFICATION.
Improvements in Preparing the Surface of Zinc Plates for
Lithographic Purposes.
I CLEMENT GEORGE BERNARD BROCKLEHURST of Claremont Place Peel Causeway
Bowden in the County of Chester Lithographer do hereby declare the nature of this
invention to be as follows:-
The object of this invention is so to prepare the surface of zinc plates that they
can be drawn or written upon by ordinary lithographic ink and used as a substitute
for lithographic stone for printing from by the ordinary lithographic process.
Before surfacing the plates it is requisite to clean the same thoroughly which I
effect by means of dilute sulphuric acid reduced with water sufficiently to just clean
and purify the surface of the plate; and I then apply a coating of lead over the
pure zinc surface by dipping the plate in a solution composed of the following
ingredients,
Two tea spoonsful of sugar of lead.
Two tea spoonsful of nitric acid.
Half a pint of water.
This will have the effect of instantly turning the surface black but on washing
the same well off it will be found that the surface is coated with a clean dull
surface of lead of light grey color.
The suface of the plate can now be written or drawn upon by means of ordinary
lithographic ink and treated and printed from in the same manner as a lithographic
stone.
GEORGE DAVIES,
4, St. Ann's Square, Manchester, Agent for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Preparing the Surface of Zinc Plates for
Lithographic Purposes.
I CLEMENT GEORGE BERNARD BROCKLEHURST of Claremont Place Peel Causeway,
Bowden in the County of Chester, Lithographer, 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 :-
The object of this invention is so to prepare the surface of zinc plates that they
can be drawn or written upon by ordinary lithographic ink and used as a substitute
for lithographic stone for printing from by the ordinary lithographic process.
Before surfacing the plates it is requisite to clean the same thoroughly which I
effect by means of dilute sulphuric acid reduced with water sufficiently to just clean
and purify the surface of the plate; and I then apply a coating of lead over the
pure zinc surface by dipping the plate in a solution composed of the following
ingredients :-
:-
.
Two tea-spoonsful or about one ounce of sugar of lead,
Two tea-spoonsful or about one quarter ounce nitric acid.
Half a pint, or nearly balf a pint of water.
This will have the effect of instantly turning the surface black but on washing
the same well off with water it will be found that the surface is coated with a clean
dull surface of lead of a light grey color.

page_text: I prefer after washing with water as before described to again wash the plate
with a very dilute solution of acetic acid in order to remove all trace of grease from
the prepared surface.
The surface of the plate can now be written or drawn upon by means of ordinary
lithographic ink and treated and printed from in the same manner as a lithographic
stone.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what I
claim is
-
The preparation of the surface of zinc plates for lithographic purposes substan-
tially as hereinbefore described.
Dated this 19th dow of March 1000
GEORGE DAVIES,
4, St. Ann's Square, Manchester, Agent for the Applicant.