Improvements in the Manufacture of Plates for Printing.
Year: 1899

page_text: Date of Application, 3rd Feb., 1899
Camentala Onnsification
Last 14th July 1000 Ascented
10th Au
1000
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Plates for Printing.
I, GEORGE RICHARD HILDYARD, of 32, East Dulwich Road, in the County of
Surrey, Color Printer, do hereby declare the nature of this invention to be as
follows;-
-
"
My invention has reference to the manufacture of zinc or other plates for print-
ing and more particularly for fine or color printing. In ordinary lithographic
printing the water employed tends to stretch the paper and the acid and gum
used tend to " rot the work while the closest work bungs up" because it is all
on the same level. If on the other hand typographic machines are employed for
fine or color printing the work which ought to leave off the softest has the
hardest and sharpest edge and it is practically impossible to get the soft drawing
of the lithographic draughtsman properly reproduced while for the whites
that are to appear on the picture it is necessary to gouge or rout the corre-
sponding parts of the plate entirely out so that it is not practicable to have a
series of designs at say a few inches apart on the same plate.
23
66
The object of my invention is to avoid the above drawbacks while preserving
the good points of both the lithographic and typographic methods of printing.
According to my invention I break up or alter the structure of the parts of the
surface of the plate between the different designs of a series, and also of any parts
that correspond with "whites" in the designs so that what I may term a uniform
rottenness or in other words an extremely fine grain with needle point like
tops is produced so fine that these parts will take up such a miscropic quantity
of ink that the paper or other material brought in contact with them without
pressure picks up none. The breaking up or alteration of the structure of the
surface as above described can be effected in any well known way such for
example as by applying a very fine spray of ink or resist to the plate and then
etching in the usual way in a rocking bath; but I find it difficult to obtain
sufficient fineness in any of these ways to produce good work and I therefore
preferably employ the following novel method.
Having transferred to or drawn upon the plate the design or designs to be
reproduced in the required positions and having placed the work under acid
resist I bite out the plate to a suitable depth, say equal to the thickness of a six-
penny piece. I then proceed as follows:-I take a tacky substance such for
example as a lithographic varnish with which may be mixed sufficient bronze
or Chinese blue to tint it, and generally a little oil to thin it. I then distribute
the tacky substance very evenly upon the zinc plate in as thin a coating as possible
and this may be effected by "whirling on," pouring and letting float, rolling
dabbing or otherwise. I find it desirable to have in stock several solutions of the
tacky substance of different consistencies, the variation being obtained by the use
of more or less oil, turpentine, paraffin, methylated spirit or the like and I use
whichever solution is best adapted for the purpose according to the state of
moisture and temperature of the surrounding atmosphere, a damp atmosphere
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page_text: makes a thick solution and a warm atmosphere a thinner solution desirable. It
is best to make a preliminary test by means of a small piece of zinc.
I next submit the plate to the action of a biting or etching solution preferably
composed of commercial nitric acid and water in the proportion of about 2 to 4 oz.
of acid to 80 oz. of water. This solution can be applied to the plate in various
ways, as for example by pouring it on to and then off the plate, or by dipping the
plate in a non-rocking bath of the solution and then after removing the plate
rinsing it with cold water, any residue of varnish should be sponged off. It is
best to submit the plate to several of these acid treatments successively, three by
preference, and to increase the strength of the solution every time. For instance
for the three successive treatments I should employ solutions containing respec-
tively 2, 3 and 4 oz. of acid to 80 oz. of water. Solutions of the several strengths
should be kept in stock.
The action of the acid when applied as described to a zinc plate which has
a thin coating of a tacky substance such as that described is to break up or alter
the structure of the surface of the plate between the different designs and of
any parts that correspond with whites in the design and to thereby produce a
uniform rottenness of very fine grain as herein before explained so that when the
plate is used to print from, these parts will take up a very minute quantity of
ink and will give up none to the paper or material printed upon,
D t 1
1
1
T
Improvements in the Manufacture of Plates for Printing.
I, GEORGE RICHARD HILDYARD, of 32, East Dulwich Road, in the County of
Surrey, Color Printer, 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 has reference to the manufacture of zinc or other plates for print-
ing by the relief plate or type printing process and more particularly for fine or
color printing. In ordinary lithographic printing the water employed tends to
stretch the paper and the acid and gum used tend to rot" the
work while the closest work bungs up" because it is all on the
same level. If on the other hand typographic machines arc employed
for fine or color printing the work which ought to leave off the softest
has the hardest and sharpest edge and it is practically impossible to get
the soft drawing of the lithographic draughtsman properly reproduced, while for
the whites" that are to appear on the picture or between picture and picture,
if such whites exceed about an inch in diameter, it is necessary to entirely gouge
out or rout out the corresponding parts of the plate leaving apertures or open-
ings therein so that it is not practicable to have a series of designs at say a few
inches apart on the same zinc plate if of the ordinary thickness.
*
*
23
The object of my invention is to avoid the above drawbacks while preserving
the good points of both the lithographic and typographic methods of printing and
to enable printing to be effected without the use of water acid or gum as usual
in lithography.
According to my invention I break up or alter the structure of the parts of the
surface of the plate between the different designs of a series, and also of any parts
that correspond with " whites" in the designs in such manner that what 1 may

page_text: ::
term a uniform "rottenness or in other words what appear to be an extremely
fine grain with needle point-like tops is produced so fine or of such peculiar
nature that these parts although accepting a small quantity of ink from the ink-
ing rollers when manipulated in the ordinary manner as in typographic printing
will not transfer such ink to the paper while printing. It is possible to obtain this
breaking up or alteration of the structure of the surface as above described in
the ways now in use for breaking up the surface for light work in pictures, (such
for example as by applying a very fine spray of ink or resist to the plate and
then etching with acid in a rocking bath) provided they be done with extreme
and unusual fineness but I find it difficult to obtain sufficient fineness in any of
these ways to produce good work and I therefore preferably employ the follow-
ing novel method :-
Having transferred to or drawn upon the plate by any usual process the design
or designs to be reproduced in the required positions and having placed the work
under acid resist I bite out the plate to a suitable depth, say equal to the thick-
ness of a sixpenny piece or about one millimetre. This biting out although very
desirable is however not essential. I then proceed as follows:-I take a tacky
substance such for example as a lithographic varnish with which may be mixed
sufficient bronze blue or Chinese blue to tint it, and generally a little oil to thin
it. I then distribute the tacky substance very evenly upon the zinc plate in as
thin a coating as possible and this may be effected by whirling on," pouring
and letting float, rolling, dabbing or otherwise; I prefer rolling. I find it
desirable to have in stock several solutions of the tacky substance of different
consistencies, the variation being obtained by the use of more or less oil, tur-
pentine, paraffin, methylated spirit or the like, and I use whichever solution is
best adapted for the purpose according to the state of moisture and temperature
of the surrounding atmosphere; a damp atmosphere makes a thick solution and
a warm atmosphere a thinner solution desirable. It is best to make a preliminary
test by means of a small piece of zinc.
I next submit the plate before the coating of the tacky substance has become
dry to the action of a biting or etching solution preferably composed of com-
mercial nitric acid and water in the proportion of about 2 to 4 oz. of acid to 80 oz.
of water. The stronger the solution the sharper but the less fine will be the
grain produced. This solution can be applied to the plate in various ways, as for
example by pouring it on to and then off the plate, or by dipping the plate in
a non-rocking bath of the solution and then after removing the plate, rinsing it
with cold water; any residue of varnish should be sponged off. It is best to
submit the plate to several of these acid treatments successively, three by pre-
ference, and to increase the strength of the solution every time. For instance,
for the three successive treatments I should employ solutions containing respec-
tively 2, 3 and 4 oz. of acid to 80 oz. of water.
The action of the acid when applied as described to a zine plate which has a
thin coating of a tacky substance such as that described is to break up or alter
the structure or nature of the surface of the plate between the different designs
and of any parts that correspond with whites in the designs and to thereby pro-
duce a uniform rottenness or very fine grain as herein before explained so that
when the plate is used to print from, these parts do not transfer any ink to the
paper or material printed upon and no water is necessary in order to obtain this
effect.
Plates manufactured according to my invention can be employed either in
typographic or lithographic machines.
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. In the manufacture of plates for printing, the mode or process hereinbefore
described of treating the plates, which mode or process consists in breaking up

page_text: or altering the structure or nature of the parts of the surface of the plate between
the designs thereon and also of any parts that correspond with whites in the
designs into an extremely fine grain with needle point-like tops, whereby the
said parts will not in the printing process transfer any ink to the paper or other
material brought in contact therewith, no water being necessary to produce this
effect, substantially as described.
2. The carrying out of the mode or process claimed in Claim 1 by applying
to the design-bearing plate (preferably after having first bitten it out to a suit-
able depth) a thin coating of a tacky substance such as a lithographic varnish
and then submitting the plate to the action of a biting or etching solution, sub-
stantially as set forth.
3. The manufacture of plates for printing in the manner hereinbefore described.
J. C. MEWBURN & ELLIS,
55 and 56, Chancery Lane, London, Chartered Patent Agents.