AN IMPROVEMENT IN THE ART OF MULTIPLYING CERTAIN DRAWINGS AND ENGRAVINGS, OR IMPRESSIONS
Year: 1834

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, SAMUEL
GARNER, of Lombard Street, in the City of London, Gentleman, send
greeting.
WHEREAS His present nrost Excellent Majesty King William the Fourth,
by His Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Fifteenth day of November, in the fifth year of His reign,
did, for Himself, His heirs and successors, give and grant unto me, the
said Samuel Garner, His especial licence that I, the said Samuel Garner, my
exors, admors, and assigns, or such others as I, the said Samuel Garner, my
exors, adiñiors, or assigns, should at any time agree with, and no others, from
time to time and at all times during the term of years therein expressed,
should and lawfully might make, use, exercise, and vend, within England,
Wales, and the Town of Berwick-upon-Tweed, the Invention in my possession,
in consequence of communication made to me by a certain Foreigner residing
abroad, of "AN IMPROVEMENT IN THE ART OF MULTIPLYING CERTAIN DRAWINGS
AND ENGRAVINGS, OR IMPRESSIONS;" in which said Letters Patent there is
contained a proviso obliging me, the said Samuel Garner, by an instrument in
writing under my hand and seal, particularly to describe and ascertain the
nature of the said Invention, and in what manner the same is to be performed,
to be enrolled in His said Majesty's High Court of Chancery within the space
of six calendar months next and immediately after the date of the said recited
Letters Patent, as in and by the same, reference being thereunto bad, may
more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Samuel Garner, do hereby declare that the nature of the said Invention
consists in the formation, preparation, and treatment of plates of zinc in such
a way as fits them more perfectly than has been done by methods previously
employed for the same purposes for which the slabs of stone are used as
instruments for the multiplication of copies of writings, plans, or designs in
the art of lithography. For the purposes of the art which may be called
zincography preference is given to metal of the purest quality. The metal is
to be cast in suitable moulds into plates of uniform thickness and of requisite
dimensions, either of the size for use, or calculated for extension under the
rollers when it is deemed desirable, as in the generality of cases I consider it
advisable. In order to give to the metal greater density than it possesses
in its simply cast form, the plates are to be subjected to the pressure
of a pair of metal rollers, passing them through at a temperature at
which the metal is malleable, alternately in the direction of the length and
breadth of the two superficial dimensions of the plates, in order to prevent
the metal from taking a fibrous texture, as it does in some degree when
repeatedly rolled in only one direction. The action of the rollers thus
managed produces a more uniform condensation of the metal than can be
effected by plannishing with the hammer. The cast plates, whether subse-
quently laminated or not, are to be brought to accurate uniformity of thickness
by being planed on one or both of their faces by a planing engine, such as is
now commonly used for planing the surfaces of other metals. By these
means an accurately flat working face is obtained, which conduces essentially
to the more certain and uniform action of the press in the operation of working
off the impression. To render the surface of the metal better adapted to
receive the marks or lines intended to be multiplied by impression therefrom,
it is adviseable to impart to it a certain roughness, termed technically a grain.
This is effected by rubbing the surface to be grained with some cutting
substance in a pulverulent form, such as silicious sands, emery stone or
marble dust, pounded pumice, rotten stone, charcoal powder, or other such
materials, having the requisite property of abrading the metal; some such
substances may be used for the purpose in masses or lumps, .as pumice stone,
charcoal, &c. These materials may be employed with water or other non-
solvent liquid, being rubbed upon the metal surface in all directions until an
uniformity of grain is produced. Either two plates may be used to grind each
other, or a muller may be employed, or leather or other soft substance may
be the instrument for the application of the cutting powder to the metal.
The fineness or coarseness of the grain to be produced will of course regulate
the fineness.or coarseness of the grinding material to be used, but in all cases

page_text: it must be guarded against applying matters of such coarseness as will cut
deeply into the plate, it being the object to produce a roughness of surface of
regular grain. Sometimes, perhaps, it may be useful to give a different grain
to different parts of the same plate, with the view to accomodate the
artist in assisting to impart a variety of character to his work.
This can be
done by using the grinding materials of different qualities in different parts of
the plate, conducting the operation by hand with such partial applications as
may be indicated.
The grinding completed, the material must be washed
off, and the plate may be cleansed from impurities to prepare it for the
reception of the writing or design by washing with a solution of alcali, either
potass or soda, caustic or subcarbonated. The lines or traces to be multiplied
from the zinc plate are made thereon by similar materials and preparations to
those used for the like purposes in the art of lithography. This being done,
either by hand or by transfer, they are to be fixed and prepared for the sub-
sequent operations by brushing over the face of the plate an accidulous
liquor, such as the one which may be prepared in the following manner :-
Boil in a pint of water about one ounce and a quarter of bruised gall nuts
until the fluid is reduced one third; pass the decoction, when cool, through a
sieve or fine linen strainer to separate the clear liquor, to which add about two
flui-drachms of nitric acid, and three or four drops of muriatic acid. This
formula may be varied as to the proportions of the acids, according to the
nature or strength of the work to be fixed, a weaker acid for the more delicate
work. The accidulous liquor may be brushed over the work with the tool
ordinarily employed for such purposes, and it may be left to act thereon, and
on the metal, for a longer or shorter time according to the strength of the
lines or work to be fixed; a few minutes will commonly suffice, but no injury
appears to result from a longer time. The plate should then be washed with
clean water to free it from the acid, and then the work may be covered with
gummed water, as is done on stone. Other acidulous liquors than the one
above described may be made use of for fixing the work upon the plate, such
as any diluted acid, the action of which on the metal will be moderate, or
solutions of many of the super-acid salts, for example, muriate or nitro-
muriate of tin; but for general purposes I prefer the preparation above
described, and claim to use, where convenient or indicated for special purposes,
any other form or preparation of ascidulated liquor. The zinc plates, pre-
pared and treated in the way herein described, answer for the reception and
redelivery by impression of all the different kinds of work now usually
executed by means of stone in the art of lithography, and equalling the stone
in all the properties dependent on surface; the zinc plates have the great

page_text: superiority of being able to bear the action of other kinds of presses than
those which have been especially adapted to the working off impressions from
The copper-plate roller press, the ordinary type press, and others
giving adequate pressure over the whole surface of the plate, may be employed
with due effect in pulling impressions from the zinc plates.
stone.
In the processes herein described for the formation, preparation, and treat-
ment of plates of zinc, to fit them more effectually than they have heretofore
been found for the purpose of multiplying copies by printing of lines, traces,
or markings made by certain materials upon their surfaces, consecutively used,
as now indicated, either to the whole extent or partially, by the omission of one
or more of the processes, for instance, condensation of the metal between
rollers, or modified, as by change of material, to produce certain effects, for
instance, graining and fixing the lines or design upon the metal, consists the
Invention for which I have obtained the grant of the herein partially recited
Letters Patent. And such Invention being, to the best of my knowledge and
belief, entirely new and never before used within that part of His said
Majesty's United Kingdom of Great Britain and Ireland, His said Dominion
of Wales, or Town of Berwick-upon-Tweed, I do hereby declare this to be my
Specification of the same. And I do verily believe that this my said Speci-
fication doth comply in all respects fully, and without reserve or disguise, with
the proviso in the said herein-before in part recited Letters Patent contained;
wherefore I do hereby claim to maintain exclusive right and privilege to the
said Invention.
In witness whereof, I, the said Samuel Garner, have hereunto set my
hand and seal, this Fifteenth day of May, in the year of our Lord One
thousand eight hundred and thirty-five.