Improvements in the Preparation of Surfaces for Lithographic and.. other Printing.
Year: 1894

page_text: Date o' Application, 5th Feb., 1894
Complete Specification Left. 7th Nov., 1894-Accepted. 8th Dec., 1894
PROVISIONAL SPECIFICATION.
Improvements in the Preparation of Surfaces for Lithographic and..
other Printing.
I, GUSTAV HENRY BLOCK, of 33, Mossbury Road, Clapham Junction, in the
County of London, Lithographer, do hereby declare the nature of this invention
to be as follows:-
My invention relates to the preparation of lithographic and other printing
surfaces and has for its object to produce on lithographic stones, and zinc and
other metal plates grained, stippled or lined surfaces more economically and
expeditiously than heretofore.
According to my invention the stone or metal plate to be prepared is first:
cleaned in the usual manner and then the grain, stipple, linework or the like is
transferred to the stone or plate in the usual way by lithography or photography
from a previously prepared or permanent original. I next roll up this transfer
with a suitable acid proof composition and then etch the design to the necessary
height by means of acid.
The etching being completed I remove the composition and destroy the grease
which the design contains with an alkaline or other suitable solution. The
surface of the plate or stone thus cleaned is then sensitized after which an artist:
or draughtsman by using a litho crayon can produce designs the lines of which
are interrupted or broken according to the nature of the ground thereby producing
a combined chalk and stipple effect.
If a design or picture is transferred to my prepared surface by photography
the lights and shades are broken up by lines, dots, grains or the like.
If thick metal plates are to be prepared for typographic printing the design or
picture prepared in the above way is etched high.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Preparation of Surfaces for Lithographio and
other Printing.
I, GUSTAV HENRY BLOCK, of 33, Mossbury Road, Clapham Junction, in the
County of London, 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:-
My invention relates to the preparation of lithographic and other printing
surfaces and has for its object to produce on lithographic stones and zinc and other
metal plates, grained, stippled or lined surfaces.
According to my invention the stone or metal plate to be prepared is first
cleaned in the usual manner and then the grain, stipple linework or the like is
transferred to the stone or plate in the usual way by lithography or photography
(or otherwise) from a previously prepared or permanent original. I next roll up
this transfer with a suitable acid proof composition and then etch the design to the
necessary height by means of acid.

page_text: The etching being completed I remove the composition and destroy the grease
which the design or pattern contains, with an alkaline or other suitable solution.
The surface of the plate or stone thus cleaned is then sensitized.
For sensitizing a lithographic stone surface prepared in the above manner
I preferably make use of a solution consisting of 4 grammes of acetic acid added to
6 grammes of alum dissolved in 100 grammes of water. After this solution has
been laid on the plate for a minute or so it is rinsed off with clean water and then
the surface is rubbed over with a paste of carbonate of magnesia and water and
again rinsed with water and dried.
This operation will neutralize any acid or alkaline matter left on the stone
surface and also the carbonate of magnesia will combine with the carbonate of
lime of which the lithographic stone consists to a great extent; also the application
of the carbonate of magnesia enables the stone surface to more readily receive the '
greasy chalks and inks for lithographic purposes than it would otherwise do.
For sensitizing a zinc or other metal plate so as to render it fit for use for
lithographic purposes without applying any coating, I prefer to adopt the treatment
described in the Specification of my former Patent No. 595 of 1894, that is to say,
I clean the plate and destroy the grease by means of an alkaline solution and then
place the said plate in a bath composed of nitric acid, alum and water in the
proportions of say, nitric acid one quart, alum three pounds and water fifty quarts,
for the purpose of oxidizing the surface of the plate, the bath being shaken all the
time the plate remains therein. When the plate has been in this bath for about
half a minute it is taken out and rinsed with water and the oxide which has formed,
is removed by rubbing with a sponge or flannel; the plate is then again placed in the
bath and left therein until oxide ceases to form thereon, whereupon the plate is
removed and cleaned from oxide.
This operation gives the pattern on the plate a certain roughness or grain and
produces a good grip for the lithographic crayon. The plate is finally rubbed over
with carbonate of magnesia to neutralize any acid and to remove any particle of
oxide which may adhere in the lower parts of the pattern on the plate. After
being well rinsed with water and dried the surface is ready for the artist or
draughtsman who by using a litho crayon can produce designs the lines of which
are interrupted or broken according to the nature of the ground thereby producing
a combined chalk and stipple effect.
If a design or picture is transferred to my prepared surface by photography the
lights and shade are broken up by lines, dots, grains or the like. To produce a
photographic printing surface it is necessary to etch the pattern higher than for
lithographic purposes.
If thick metal plates are to be prepared for typographic printing the design or
picture prepared in the above way is etched high.
My processes for sensitizing lithographic and other printing surfaces are
applicable to plain plates as well as to plates prepared as above described.
-
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
-
1. The hereinbefore described process for preparing lithographic and other
printing surfaces, such process consisting in first cleaning the surface of the stone
or metal plate, then transferring to the surface the grain, stipple, linework or the
like, rolling up the transfer with an acid-proof composition and etching the design
by means of acid, removing the composition and finally sensitizing the surface of
the stone or plate, substantially as hereinbefore described.
2. In preparing lithographic and other printing surfaces in the manner described
in the preceding claiming clause the use of a solution of acetic acid and alum, the
surfaces being subsequently rubbed over with carbonate of magnesia, substantially
as described.

page_text: 3. Lithographic stones and metal plates having their printing surfaces prepared
as, and for the purpose, herein before described.
Dated the 7th day of November 1894.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.