proved method of Decorating Metal.
Year: 1899

page_text: Date of Application, 12th May, 1899
Complete Specification Left, 10th. Feb., 1900-Accepted, 12th May, 1900
proved method of Decorating Metal.
We, JAMES PATERSON, Jeweller, of 17, St. Giles Street, Edinburgh, and WILLIAM
DICKSON, Photographer, of No. 23, Lutton Place, Edinburgh, both in the County
of Midlothian, Scotland, do hereby declare the nature of this invention to be as
follows:
:-
This invention relates to an improved method of decorating metal and has
for its object to engrave or etch surfaces, preferably of precious metal, with greater
efficiency and economy than is effected when following methods hitherto generally
employed.
According to our invention we coat the part of the metal surface to be etched
or engraved, with sensitive enamel, and protect such parts of the said metal
surface as are not to be etched or engraved, with varnish or other acid resisting
substance. We then print a photograph of the decoration on the sensitised surface
from a direct negative, develop and wash the same and then burn it onto the
metal. The surface of the metal to be etched is then converted to a form in which
it can be readily attacked by an acid and then etched or engraved by immersing
it in a suitable bath. The etched metal is then cleaned or bleached, washed, dried,
and burnished, after which it may be oxidised gilded or finished in any desired
manner.
When treating for example a silver surface, we coat all parts of the article
that it is not required to etch or engrave, with varnish, bees wax, or other acid
resisting substance; leaving the surface to be engraved or etched, unprotected.
The surface to be engraved or etched is then polished or cleaned to remove dirt
or grease. Such polishing and cleaning may be effected by suitable polishing
paste, tripoli powder, a weak solution of nitric acid and alum, or other means.
The said surface is then coated with a sensitive enamel which is then dried
and hardened. The sensitive enamel preferably consists of fish glue, bichromate
of ammonium, and water.
""
The metal is then cooled and a direct photographic negative, which may have
been photographed through a suitable screen or in other suitable manner such
for instance as by the " dust"
or "bitumen
perature as the metal article and placed upon the sensitised surface.. A photograph
process, is brought to the same tem-
of the required decoration is thus printed on the metal surface.
The fish glue is then dissolved by placing the article in water; and the surface
under treatment is then coated with a suitable dye, and developed and washed
with water. After which the picture is burnt in, preferably by subjecting the
everse side of the article to the heat of a gas stove or spirit lamp.
The metal article is then placed in a bath of potassium bichromate and water
nd subjected to an etching or engraving bath of sulphuric acid and water; the
ichromate of potash converting the silver surface with which it comes in contact
nto chromate of silver which can be acted upon by the sulphuric acid.
ngraving or etching may be effected by treatment with an iodine bath to produce
Or the
odine of silver and then with a bath of cyanide of potassium. In either case the
CD 072

page_text: silver in the spaces formed by the screen, is eaten away or dissolved. If during
this etching or engraving, the enamel shows signs of giving way it should be
washed off, dried, inked and then replaced in the bath to complete the etching.
The enamel or ink is then washed off and the etched surface dried and then
burnished.
The article may then be oxidised, gilded, enamelled, or otherwise treated as
required.
Before burnishing, the article may be whitened by heating it to a cherry red,
dipping it in dilute sulphuric acid, and then washing and drying. Or the article
may be placed in the plating bath for a few minutes to effect the same purpose.
We have described the process as applied to a silver surface, but a gold surface
may be similarly treated. We may also, if required, apply the process to baser
metals such as German silver.. The etching bath or baths being varied to suit
the requirements of the metal treated. In treating German silver, for instance,
we preferably employ perchloride of iron and nitric acid.
The photographic design employed may be a picture of a person, animal, or of
any suitable object, drawing, print, decorative design or the like, and may be
applied to any surface whether the same be flat, convex, concave or of other form.
Dated this 12th day of May 1899.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicants.
An Improved Method of Decorating Metal.
We, JAMES PATERSON, Jeweller, of 17, St. Giles Street, Edinburgh; and WILLIAM
DICKSON, Photographer, of No. 23, Lutton Place, Edinburgh, both in the County
of Midlothian, Scotland, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
This invention relates to an improved method of decorating metal and has
for its object the engraving or etching of surfaces, more especially of precious
metal, with greater efficiency and economy than can be effected when following
methods hitherto generally employed.
According to our invention we coat the part of the metal surface to be etched
or engraved, with sensitive enamel, and protect such parts of the said metal
surface as are not to be etched or engraved, with varnish or other acid resisting
substance. We then print a photograph of the decoration on the sensitized surface
from a direct negative, develop and wash the same and then burn it onto the
metal: The surface of the metal to be etched is then preferably treated with a
chemical etching solution and the engraving or etching then completed by
immersing the said surface in another chemical solution. The etched metal is
then cleaned or bleached, washed, dried and burnished, polished, oxidised, gilded
or finished in any desired manner.
When treating for example a silver surface, we coat all parts of the article
that are not to be engraved or etched, with varnish, bees wax or other acid resist-
ing substances; leaving the surface to be engraved or etched, unprotected.
The surface to be engraved or etched is then polished or cleaned to remove dirt
or grease. Such polishing and cleaning may be effected by suitable polishing
paste, tripoli powder, a weak solution of nitric acid and alum, or other means,

page_text: Care must be taken that the surface is free from scratches or marks of any
kind.
The surface under treatment is then coated with a sensitive enamel which is
then dried and hardened, preferably by submitting it to the heat of a gas or other
5 stove. The sensitive enamel preferably consists of fish glue three (3) ozs.,
bichromate of ammonium five (5) scruples and water eight (8) ozs.
The metal is then allowed to cool sufficiently to permit it to be brought into
contact with a photographic negative of the required design, which has been
warmed to remove moisture. The design is then printed on the sensitised surface
in the usual manner by exposure to light.
The parts of the fish glue enamel not acted upon by light are then dissolved
and the design is developed by placing the article in water, the surface under
treatment is then coated with a suitable dye to render the picture or design clearly
visible. After which the picture is burnt in, preferably by subjecting the reverse
side of the article to the heat of a gas stove or spirit lamp, until the enamel
acquires a rich brown colour.
The metal article is then placed first in a bath of potassium bichromate, and
the etching or engraving is then completed by means of a second bath of sulphuric
acid and water. The first: bath is preferably composed of a saturated solution of
bichromate of potassium to which are added a few drops of sulphuric acid. The
second bath is preferably composed of eighteen (18) parts of water to one (1) part
of sulphuric acid!
Or we may employ other chemicals or combinations of chemicals. For instance;
we may employ a bath of iodine, followed by a bath consisting of a 10 per cent.
solution of cyanide of potassium. The iodine bath may conveniently be composed
of iodine (re-sublimed) twenty-five (25) grains, iodine of potassium one hundred
and fifty (150) grains, water 5 ounces.
+
If during the etching or engraving the enamel shows signs of giving way, it
should be washed off, and the metal surface should be dried, inked with acid-
resisting ink and then replaced in the bath or baths to complete the engraving or
etching.
The surface under treatment should be washed with water after being subjected
to the first solution or bath and before being subjected to the second solution
or bath, and the said surface should be treated alternately with the said solutions
until it is engraved to a sufficient depth.
The enamel or ink is then washed off preferably with
potash and the engraved surface is dried."
66
American" or caustic
The metal article should then be whitened, preferably by heating it to a cherry
red, dipping it in dilute sulphuric acid and then washing and drying it. Or the
article may be placed in the plating bath for a few minutes, to effect the same
purpose.
The metal surface with the decorative design engraved upon it, is then burnished
to produce a distinct and clearly defined effect.
The pictures or designs may also be polished, oxidised, gilded enamelled or
otherwise treated as required. If it is desired to oxidise or gild the ground, and
leave the surface white by "matting" or otherwise, a photographic positive should
be used instead of the negative and the oxidising or gilding done in the usual
manner.
The photographic negative employed may have been photographed through a
suitable screen, or by the "dust" of "bitumen "
and dust process, or a spray process, or any method of producing a grain or halftone
process; or a combined screen
icture may be employed. For inscriptions, floral borders, drawings in line and
imilar work, the screen or dust process is not required.
When treating a gold surface we adopt for our purpose the process known as
lectro-etching.
An enamel or film photograph is applied to the gold in a similar manner to
hat described for the treatment of silver. A bath is prepared, composed preferahl..

page_text: of a ten (10) per cent. solution of cyanide of potassium. The gold article may
then be connected to the positive electrode, and a piece of gold or other metal
connected to the negative electrode, of a Daniell or other electric battery. Both
the gold article and the piece of gold or other metal are then suspended in the
said cyanide bath as is well understood. A very weak current of electricity is
preferably employed. The exposed parts of the gold article are etched or dissolved
and the decorative design or picture is thus produced. The enamel or film is
then cleaned off and the gold article may then be gilded coloured or pickled in
the usual manner in order to make it as pale in colour as possible, and then
finished by burnishing as described in the treatment of silver.
Silver may be engraved or etched in a similar manner to the gold, but this
method is inconvenient, more expensive, slower, and less effective in its results
than the process herein before described for the treatment of silver.
We may also if required, apply the process to the treatment of baser metals,
such as "German" or nickel silver, the etching bath or baths being varied to
suit the requirements of the metals treated.
In treating "German". or nickel silver for instance, we preferably employ a
solution of perchloride of iron, of 35 or 40 degrees Beaume. The engraved or
etched surface is then silver plated or gilded in the usual manner and finished
as described above in the treatment of silver.
<<
"
When treating a German or nickel silver article already plated with silver
or gilded, the process is the same as that above described with reference to a
silver or gold article, provided the plating is thick enough to permit the required
depth of engraving or etching; otherwise, the plating is removed in the usual
manner from the part or parts to be operated upon. The photographic design is
then put on the base metal and the engraving or etching effected with perchloride
of iron as already described; the engraved part or parts are then re-plated in the
tisual manner of partial plating, and finished by burnishing as above described.
It is obvious that the base metal surface may be thus engraved before being
plated and then plated with precious metal and burnished.
The photographic design may be a picture of a person animal, landscape, or
of any suitable object, drawing, print, decorative design or the like, and may
be applied to any surface whether the same be flat, convex, concave or of other
form.
The treatment of curved surfaces is preferably as follows.
A thoroughly clean piece of glass, of the same size as the photographic negative,
is coated preferably with a solution or mixture composed of stripping collodion
one (1) oz., and castor oil ten (10) drops. After the collodion is quite dry it is
coated with sensitive fish glue enamel, then dried, printed from the photographic
negative and developed in a similar manner to that described above when treating
a metal surface direct; excepting that the negative should be a reversed one,
reduced in the usual manner.
:
The composite film thus produced with the photograph upon it is then cut to the
required size and shape, care being taken that the incisions are clean. A piece
of transparent paper is cut the same shape as, but about inch larger than the
film, then damped and laid on the film and squeegeed down the paper is then
lifted by one corner, when the film will be found adhering to it, the collodion
side uppermost.
Another similar piece of damped paper is then laid on the
collodion side and squeegeed down. The film is now between two papers. The
paper is next removed from the enamel side of the film. This enamel side of
the film should now be placed on the metal article and squeegeed down in its
final position, and the remaining paper removed. The collodion side of the film
is again uppermost, and this collodion should now be removed by dissolving it,
preferably by a mixture of equal parts of ether and alcohol. The subsequent
treatment of burning in, engraving or etching and finishing, is the same as that
already described.
This composite film method may also be applied to flat surfaces,

page_text: Instead of using the sensitive enamel or composite film above referred to for
receiving the photograph of the required design on the metal, preparatory to the
engraving, the carbon tissue transfer process, or "Smith's" dry enamel or any
other process for producing an enamel or film photograph on the metal, may be
adopted; always provided that such enamel or film is of a suitable nature to
resist the action of the chemical baths or mordants.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is:
1. In a photo-engraving or etching process for decorating a precious metal
surface, the etching or engraving of the said surface with two separate chemical
solutions, substantially as and for the purpose specified.
2. The decoration of a precious metal surface, by applying an enamel or film
photograph of the required design to said surface, etching or engraving and then
burnishing the design on said metal surface, substantially as described for the
purpose specified.
3. The method substantially as described for decorating precious metal, or base
metal coated with precious metal, for the purpose specified.
יזתו...
101
רד
1
100
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicants.