IMPROVEMENTS IN ТПЕ MANUFACTURE OR PRODUCTION OF A SUBSTITUTE FOR LITHOGRAPHIC STONES
Year: 1884

page_text: I CHARLES EDWIN LAYTON of Farringdon Street in the City of London
Stationer do hereby declare the nature of said invention for "IMPROVEMENTS
IN
ТПЕ MANUFACTURE OR PRODUCTION OF A SUBSTITUTE FOR LITHOGRAPHIC
STONES to be as follows :-
"
The present invention relates to further improvements in the process for the
production of a substitute for lithographic stones for which Letters Patent were
granted to Herbert John Haddan (a communication from abroad by Peter Corfitz
Möller) No 2836 dated the 7th June 1883.
In carrying out the present improvements, to the solution of bicarbonate of lime
described in the Specification of the said former Letters Patent I have found it
advantageous to add alumina, magnesia, and silica before applying the solution to
the metallic surface.
The proportions which I have found to give good results are the following;
namely,
about 200 parts of the solution of bi-carbonate of lime
9 parts of dilute silica bvdrate

page_text: The calcareous deposit is produced on the metallic surface in the manner
described in the Specification of the said former Letters Patent or in any other
suitable manner such as by moistening the plates while they are on a heated
surface and this method I have found by experiment to give good results.
I sometimes find it advantageous to moisten the surfaces after having been
prepared as above described with diluto alkalino silicate.
By my improvements I obtain a surface more suitable than heretofore for the
various purposes for which lithographic stones are used.

page_text: for Lithographic Stones.
I, CHARLES EDWIN LAYTON, of Farringdon Stroet, in the city of London,
Stationer, do hereby declaro the nature of the said invention for "IMPROVEMENTS
IN THE MANUFACTURE OR PRODUCTION OF A SUBSTITUTE FOR LITHOGRAPHIC
"
STONES and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement:—
The present invention relates to further. improvements in the process for tho
production of a substitute for lithographic stones for which Letters Patent wero
granted to Herbert John Haddan (a communication from abroad by Peter Corfitz
Möller) N° 2,836 dated the 7th Juno 1883.
In carrying out the present improvements, to the solution of bicarbonate of lime
described in the Specification of the said former Letters Patent I have found it
advantageous to add alumina, magnesia and silica before applying the mixture to
the metallic surface.
The proportions which I find by experiment to give good results are the
following, namely, about,-
200 parts of the solution of bi-carbonate of lime
3 to 12 parts of dilute silica (by which I mean silicate of potash)
2 to 8 parts of a solution of magnesia
and 3 to 14 parts of dilute alumina bydrate.
The solution of silicate of potash must be slightly alkaline and should yield
about one half per cent of silica. The solution of magnesia should be in the form
of a solution of the bi-carbonate containing about per cent of carbonate of
magnesia. The alumina hydrate which I use is in the form of an aqueous
mixture of precipitated hydrate of alumina containing about 14 per cent of hydrato
of alumina.
•
By varying the above proportions the deposits on the plates are obtained of
various degrees of hardness suitable for different kinds of lithographic work.
I find by experiment that for most purposes better results are obtained by
roughening or graining the metallic surfaces before producing the calcareous or
stony deposit thereon.
The production of the said roughened or grained metallic surfaco is effected in
any suitablo manner such as by grinding with sand, emery, or the like, or by
means of the sand blast or otherwise.
The calcareous or stony deposit is produced on the metallic surface in the manner
described in the Specification of the said former Letters Patent or in any other
suitable manner such as by moistening tho plates while they are on a heated
surface, and this method I find by experiment to give good results.
In practice I find that a good quality of deposit on the metallic surface is
obtained by first employing a mixture consisting of about 200 parts of the solu-
tion of bi-carbonate of lime, described in the Specification of the said former
Letters Patent, about 3 parts of the alkaline solution of silicate of potash, about two
parts of the solution of bi-carbonate of magnesia and about 3 parts of the aqueous

page_text: mixture of hydrate of alumina until the metallic surface has become sufficiently
covered with the deposit. I then use a small proportion (say about one sixth part
of the quantity required to produce the first deposit) of a second mixture consisting
of about 200 parts of the solution of bi-carbonate of lime, about 12 parts of the
alkaline solution of silicate of potash about six parts of the solution of bi-carbonate
of magnesia and about 14 parts of the aqueous mixture of hydrate of alumina. In
this way I obtain a combined deposit the surface of which is better finished and
better fitted for lithography than the surface of the deposit produced by the use of
the first named mixture alone.
During the process of production the deposit is occasionally rubbed or brushed 1
lightly in order to remove any non-adherent matter.
The deposit is finally washed with water.
I sometimes find it advantageous to moisten the deposit after having been
produced as above described with the slightly alkaline solution of silicate of potash
before mentioned.
By my improvements
obtain a calcareous or stony deposit or surface more
suitable than heretofore for the various purposes for which lithographic stones are
required.
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
.
1. The improved manufacture or production of a substitute for lithographic
stones by producing on metallic surfaces calcareous or stony deposits in the manner
herein before described.
2. In the manufacture of a substitute for lithographic stones the use of s
roughened or grained surfaces on the plates beforo producing the deposits as
herein before described.
3. The manufacture and use of the improved substitute for lithographic stones
as herein before described.