Year: 1893

page_text: Date of Application, 29th July, 1893
Complete Specification Left 28th Apr., 1894-Accepted, 23rd June, 1894
Kesin.
These ingredients, should be mixed with turpentine and boiled in a suitable vessel.
This coating of varnish should be applied lightly in such manner as to shew
plainly a tracing of the design (which is to be engraved) through the varnish, said
tracing having been previously made upon the stone. When the coating of varnish
is perfectly dry, the design is to be engraved upon the varnish, the lines being
traced therein with the point of a diamond or its equivalent; this should be effected
very lightly so as not to attack the stone itself but only the varnish.
It is well to employ a pointed diamond.
A solution is then prepared composed of the same varnish, with turpentine and a
small quantity of lithographic ink by the application of which where desired,
protection is absolutely afforded to those parts to be left white, and which ought
not to be bitten. This done the work is commenced of biting it in.
A pencil (brush) dipped in nitric acid is passed over the surface and if the parts
are to be lightly bitten it is preferable, as soon as the acid boils a little, to wipe off
the acid with a sponge wet with clean water. This operation is repeated until the
lines are sufficiently bitten according to the tones to be obtained.
As soon as a portion of the engraving is bitten sufficiently, it should be
covered with varnish mixed with turpentine and lithographic ink.
To ascertain if the biting-in is sufficient, acetic acid solution is passed at
intervals over the engraving and washed with clear water.
This acid (which bites very weakly) produces apparent white lines shewing all
lines of the engraving, where drawn very clearly.
When the engraving is completed it is covered finally with the varnish mixed
with a little turpentine and lithographic ink and the stone goes to the printer to be
printed from in the ordinary way.
Dated this 20th day of Jul 1802

page_text: Resin.
These ingredients should be mixed with turpentine and boiled in a suitable vessel.
This coating of varnish should be applied lightly in such manner as to show
plainly a tracing of the design (which is to be engraved) through the varnish, said
tracing having been previously made upon the stone as before stated. When the
coating of varnish is perfectly dry, the design is to be engraved upon the varnish,
the lines being traced therein with the point of a diamond or its equivalent;
this should be effected very lightly so as not to attack, the stone itself but only
the varnish.
It is well to employ a pointed diamond.
All those parts to be left white, and which ought not to be bitten, are separated
from the parts to be engraved by an application of the varnish before described.
This done the work of biting it in is commenced.
A pencil (brush) dipped in a solution of nitric acid is passed over the surface,
and if the parts are to be lightly bitten it is preferable, as soon as the acid boils a
little, to wipe off the acid with a sponge wet with clean water. This operation is
repeated until the lines are sufficiently bitten according to the tones to be obtained,
and the stone goes to the printer to be printed from in the ordinary and well known
manner.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what I
claim is :-
1. In lithographic engraving, the varnish or coating material composed substan-
tially of the hereinbefore stated materials and prepared in the manner stated,
applied and acting as and for the purposes hereinbefore described.
2. The method or process of producing engravings on lithographic stones,
composing my improvements in or connected with lithographic engraving, including

page_text: the tracing of the lines with a diamond or its equivalent upon the varnish, so as not
to attack the stone itself but only the varnish, all substantially as and for the
purposes herein before described.
Dated this 20th
1004
BREWER & SON,
London and Leeds, Agents for Applicant.