Improvements in the Method of Producing Dead-gold (Silver, Platine) Decorations on China, Crockery-ware, Glass, and Enameled Metals.
Year: 1887

page_text: Date of Application, 30th June, 1887
Specification Accepted, 8th Nov., 1887
COMPLETE SPECIFICATION.
Improvements in the Method of Producing Dead-gold (Silver,
Platine) Decorations on China, Crockery-ware, Glass, and
Enameled Metals.
I, MAX FRIEDRICH LEOPOLD EHRLICH, Chemist, of No. 19 Bockenheimer
Landstrasse, Frankfort on the Main, in the German Empire 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 :-
The object of my invention is to produce dead gold-decorations on china and other
keramic articles etc. by the use of protosulphuret of gold, which is done by me, by
first applying alumina or a composition of alumina and lead or copper to the article to
he gilded, then baking the latter, and after this, brushing the protosulphuret of gold
on that part of the article's surface on which the alumina or the composition of alumina
with lead or copper was applied, being rendered thereby rough, so that the gold will
stick firmly to it and appear dead.
In the methods heretofore used in producing dead gold, silver, or platine decorations
on china and other keramic articles, a ground for the gilding was received by laying-
on or applying ground china clay or by macerating the china, but all these methods
had not been satisfactory as the rough surface produced on the china was not fine
enough to apply a dead gold cover which was consistent and even in all parts.
I avoid these deficiencies by making use of my new method which is the following:
I take alumina or a composition of alumina and lead or copper etc. and bake the
same. Hereby part of the composition or alumina is decomposed and votalized and
the product is a very finely ground clay.
This product is mixed with an enamel for instance protoxide of lead or boric acid
and treated like a common enamel as used in the manufacture of keramic-articles. All
this is ground or rubbed on a pallet with a strong varnish or turpentine and is then
applied to the article to be decorated, in a very thin coat or layer. After this coat
has been dried, the article is put into a muffle to be baked.
When the baking is finished the surface covered with the compound or composition
above described will appear finely roughed, and now the protosulphuret of gold or
silver or platine, as brought to the market for gilding purposes, is applied to it and

page_text: the article baked once more, whereafter the treated or prepared places appear in a very
rich dead gold colour.
The protosulphuret of gold can of course be used also on other places then those
which are prepared with the compound just specified and in this case the gold will
appear in parts bright and in parts dull.
A slight modification of my method consists therein that the compound is not
directly applied to the surface of the article, but first on paper and then by reprinting
to the article. There may be also any other protosulphuret applied for instance such
of silver, platine or iron, or a mixture with gold of silver &c.
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. The method of producing dead gold, silver or platine decorations on keramic
and other articles consisting of the application of a composition of a glowed and
thereby partly votalized and finely ground alumina, or alumina and lead or copper,
with an enamel to the surface of the article of the subsequent baking of the latter,
in the coating of the surface thus prepared with protosulphuret of gold, silver or
platine &c.; and of the baking of the same once more, all in the manner and for the
purpose substantially as described.