Improvements in or relating to Etching Grounds.
Year: 1895

page_text: Date of Application, 4th Apr., 1895
Complete Specification Left, 4th Jan., 1896-Accepted, 7th Mar., 1896
PROVISIONAL SPECIFICATION.
Improvements in or relating to Etching Grounds.
I JOHN BAKER of The Leys, Chipping Norton in the County of Oxford,
Printer's Manager do hereby declare the nature of this invention to be as
follows:-
The invention relates to the production of etched surfaces-relief or sunken
designs by means of transferrable acid-resisting etching grounds.
The grounds are made transferrable by spreading any kind of acid-resisting
materials upon a sheet of lithographic or other transfer paper, and, after working
the design into the ground so spread by the aid of etching needles or other hard
points, the ground so manipulated is transferred to the surface of the material
desired to be etched in the manner usual in lithographic and other transferring
thus enabling the artist or other manipulator to perform his work right-handed and
not reversed as is now done.
The transferrable grounds can be made of any suitable acid-resisting materials
alone or in combination; and the soluble basis of such grounds can be made of
partially or wholly soluble substances. Gelatinous, glutinous, or other soluble
materials for the wholly soluble. Gummy, glutinous, saccharine, farinaceous or,
other soluble or partially-soluble substance for the soluble basis. Or a cellulose,
fibrous, woolly, or otherwise bibulous substance, can be impregnated, coated, or
otherwise charged on its surface with any soluble or partially-soluble substance to
form the basis for the acid-resisting transferrable grounds.
The acid-resisting transferrable grounds can also be partially removed from the
soluble basis by impressing a flat device, engraved or cut block, metal or wooden
type, stereotype, or other plate having characters in relief or sunken, rule and type
form, toothed wheel, comb, or other material against the surface; or, the grounds
can be removed by scraping ruling or stippling or otherwise.
After the manipulated or sketched grounds are transferred to the surface of the
material to be etched, the action of the acid or metallic salt would produce a sunken
design. If a raised design is needed, the manipulated transferred ground is flowed
over with an acid resisting varnish soluble in a different solvent to that of the
transferred ground.
Dated this 2nd do of Anril 1805
Improvements in or relating to Etching Grounds.
I, JOHN BAKER of The Leys, Chipping Norton, in the County of Oxfordshire,
Printer's Manager 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 :-
This invention relates to etching-grounds and processes for the manufacture and
subsequent treatment of the same, its main object being to render such grounds
readily transferable as, for example from a surface upon which they are retained
whilst being worked on by the artist to a surface which is to be etched by acid
through the openings made in the etching-ground by the artist.

page_text: "
"
The characteristic advantage of a transferable ground is that the artist need not
as at present work "in reverse by making the right-hand side of his picture that
which is to be the left-hand side in a 'print from the final etching or vice versa, for
the new ground is not only transferable but also reversible as will hereinafter be
explained.
"
According to my invention I obtain a transferable etching-ground by placing or
forming an etching ground of an acid-resisting medium upon a layer of material
hereinafter termed a " basis which ordinarily retains the etching-ground
securely, but is readily separable therefrom when desired, either by being pulled
away from it, or by being dissolved whilst the etching-ground remains unaffected.
The acid-resisting medium should preferably be such that it can be spread upon
the basis in a liquid or viscous state and that it will thereafter dry quickly and com-
pletely and become firmly adherent to the basis or to an adhesive. facing provided
on the latter; or it may be of such a nature that it can be made into a block or
mass from which, when it is dry, thin films can be shaved, each of which will stick
firmly to the basis or to the adhesive facing of the basis, when pressed thereupon;
or it may be prepared as a solution upon which the sheet or layer of the basis is
floated to cause a film of the acid-resisting medium to adhere to it. In this last
instance the medium must not be too fluid for it is desirable to coat a face of the
basis and not to impregnate it. In any case the resulting ground must be such
that the desired portions of it are readily removable from the basis by the touch of
an etching needle or by the contact surfaces or projecting faces of type or other
design pressed upon it as hereinafter described, and yet it should not spread under
the influence of moderate heat or when pressure is applied to the back of its basis
in the operation of transferring; nor must it fail, when transferred to adhere
closely to the plate which is to be etched.
The acid-resisting medium above referred to can be made by dissolving most
kinds of lithographic transfer writing ink in turpentine, benzine or other solvent
and then spreading the solution upon any of the bases hereinafter described by
means of a printer's composition-roller, allowing the solvent time to evaporate
before the grounds are used for etching. The addition of a little printing ink (say.
about 5% of the weight of the lithographic ink aforesaid) to the dissolved writing
transfer ink facilitates the distribution of the solution but it must be used sparingly.
If however it is desired to use a larger percentage of printing-ink the ground must
alter being transferred from the basis in some such manner as is hereinafter
indicated must be strengthened or stiffened; this is effected by powdering the
ground with rosin or with "dragon's blood." An ink suited for use as an acid-
resisting medium can be made by mixing together with the aid of heat, 2 parts of
beeswax, part of Pears soap, 1 part of Mander Brothers "medium varnish,
1 part of Brunswick black, adding to the mass while in a warm state 5 parts of
spirits of turpentine, these parts being by weight. For warmer climates than that
of England the softer ingredients must be used in lesser quantities; the resulting
medium should be spread on the basis to a thickness of say go or Too of an inch.
The basis if, it is to be insoluble should be capable of being peeled off or other-
wise parted from the ground after being moistened on the back and may be for
instance lithographers' transfer-paper well coated with the coating compositions
ordinarily used such as flour or starch paste, gum or dextrine, with or without
treacle; if the basis is to be soluble it may be composed for instance of a very thin
film of gelatine with or without the addition of dextrine or of saccharine matter.
For instance an addition of dextrine equalling in weight 20% of the gelatine, or
an addition of sugar equalling in weight say 10% of the gelatine will be found
advantageous. A satisfactory basis can be made by spreading three or four coats
of a solution of gum-arabic upon sheets of demy printing paper, twenty pounds to
the ream, and rolling the surface of the sheets to smooth them when the gum-arabic
has dried.
Upon one of the herein before described etching grounds supported by such a
basis the artist or operator to produce the design, operates with etching needles or

page_text: other hand or machine tools or otherwise, and removes portions of the etching
ground from the basis. so that openings or porforations are produced in it. Or
removal of portions of the ground to produce the desired openings or perforatious
of the design may be effected by impressing upon it a block or other device having
the design in relief or in intaglio thereon; such a block or device picks up portions.
of the ground, thus producing an openwork design. For example the ground will
be very useful to the letter press printer as it will enable him to obtain from any
type forme a ground through which a plate can be etched to produce letters in
intaglio; such a plate which when printed from will produce raised or embossed
lettering on a plain back-ground, or will produce uncoloured embossed letters on a
coloured back-ground if the plate be inked. To prepare an etching-ground for use.
in etching a plate a few impressions of the type forme are pulled upon one of the
transferable etching grounds, the type forme being dry brushed between each
impression. Four impressions are sufficient to remove the desired parts of the
ground before it has become dry by evaporation of the solvent. If the ground is
in a dry state the type-forme must be heated to about blood heat (98 degrees
Fahrenheit) in which event three impressions will be sufficient to remove the
desired parts of the ground. If the forme be heated to about 120 degrees Fahrenheit
one impression will be sufficient. The same method applies to other surfaces having
characters or designs thereon.
After the design is produced in the etching-ground the ground is transferred by
being placed face downward and basis upward on the surface which is to be etched
by the acid; a few sheets of damped blotting-paper are laid on the back of the
basis and the whole is then placed in a press and pressed.
When taken out the moisture from the damped blotting-paper will be found to
have penetrated the basis which can be readily removed leaving the manipulated
ground firmly adhering by its face to the surface of the plate desired to be etched,
its back being now uppermost and the design being therefore reversed so that what
was originally at the right-hand thereof is now at the left-hand, and vice versa..
The plate is then immersed in an acid bath, or a solution of a metallic salt such as.
perchloride of iron for a copper surface or sulphate or chloride of copper for a zine
plate can be poured over it. In a few minutes the plate will be found to be etched
to a depth corresponding to the strength of acid and deeply enough for printing:
from. Any further depth desired can be obtained by subsequent treatment as for
ordinary etching.
Ordinarily the acid acting through the openings of the etching-ground produces.
a sunken design by eating into the surface exposed below the openings, but if the
design is required to be in relief the transferred ground having the open or
perforated design upon it and lying on the plate, is washed over with an acid-
resisting varnish insoluble in any solvent by which the transferred ground can be
dissolved; shellac varnish, for example would serve the required purpose. The
varnish should be allowed to dry, after which the plate must be slightly warmed
and washed over with turpentine which removes the ground, and in doing so, the
dried varnish, except where the latter is in direct contact with the plate and where,.
consequently, there is no intervening ground, that is to say except where the lines
or characters of the design occur; therefore the latter are formed upon the plate
in protective varnish and all other parts of the plate save these will be bitten or
etched when the etching acid is poured on to it so that the design will be left in
relief.
By warming the plate as above described those parts of the varnish which have
the ground underneath them (but not the parts which adhere directly to the plate)
can be caused to crack readily under very slight pressure such as is exerted for
instance by the wool employed in laying on the turpentine. Through the cracks
thus produced the turpentine is readily absorbed by the ground, which thereafter
with the desired parts of the superimposed varnish is easily removable. The
metal best suited for etching by this last-described method is zinc, having a film
or coating of copper. The first etch should be done with perchloride of iron which.

page_text: attacks the copper eating it away where not covered with the varnish left on the
plate; while for the second and final etch chloride of copper should be used which
attacks the zinc only.
The transferable grounds can be made of many acid-resisting materials, alone or
in combination and other than those hereinbefore specifically referred to by way of
example and the basis of these grounds can be made of various substances,
preferably those of a gelatinous or glutinous nature, for the wholly soluble bases
and of a gummy, saccharine, glutinous, farinaceous or other material of a viscous
or pasty nature or capable of being readily made so, for the other bases; or a
backing of cellulose or of fibrous or other bibulous substances can be impregnated
or coated or otherwise charged on the surface with any such substance or with a
soluble substance to form a basis for the acid resisting transferable grounds.
A further advantage of my invention is that a design to be etched can be drawn
on a piece of ordinary transfer paper, and have one of my transferable etching
grounds superposed upon it; the latter being transparent the design on the ordinary
transfer paper shows through it and serves as a guide to the artist in using the
etching needle or the like on the ground.
The various processes herein before described may be varied and other details of
the improvements hereinbefore exemplified altered or modified without departing
from the nature of my invention.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is;-
1. A transferable "etching-ground."
16
2. A transferable reversible etching-ground."
3. The combination of a transferable etching-ground and a basis which is readily
separable therefrom for the purpose described.
4. The combination of a transferable etching-ground and a soluble basis for the
purpose described.
5. The combination of a transferable etching-ground and a basis of any material
or mixture of materials such as herein before specified with reference to the bases.
6. The combination of a transferable etching-ground and its basis, produced by
placing the basis in a solution of the ingredients of which the ground is composed.
7. The combination with a transferable etching-ground and its basis of a backing
of bibulous material substantially as hereinbefore described.
8. A transferable etching-ground composed of or comprising lithographic transfer
writing-ink with (or without) the addition of printer's ink.
9. A transferable etching-ground composed of or comprising a mixture of bees-
Pear's soap, varnish, Brunswick black and turpentine.
wax,
10. A transferable etching-ground consisting of a film shaved or cut from a block
or mass of material.
11. Imparting a perforated or openwork design or the like to a transferable
etching-ground by impressing thereon a plate on which a design exists in intaglio
or in relief so that portions of the ground are lifted thereby substantially as
described.
.
12. Coating a transferred perforated or openworked etching-ground with varnish
and subsequently removing it and portions of the varnish from the plate so that a
design is produced by the varnish retained on the plate substantially as and for the
purpose described.
1000
JNO. BAKER.
Boult & Wade,
Agents for the Applicant.