A Process for the Production of Coloured Pictures, Writing, and the like on Glass, Porcelain, or Enamel.
Year: 1893

page_text: Date of Application, 17th July, 1893-Accepted, 9th Sept., 1893
COMPLETE SPECIFICATION.
A Process for the Production of Coloured Pictures, Writing, and
the like on Glass, Porcelain, or Enamel.
I, WENZL KNAPP of 21 Splachterstrasse Hamburg in the Empire of Germany,
Manufacturer, 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 present process has for its object to enable practically indestructible colored
pictures or letters to be imparted to straight or curved surfaces of glass, porcelain,
stoneware or enamel, as used in the production of iron utensils, by an exceptionally
simple and cheap method. The speed with which the process can be worked makes
it especially suitable for use in wholesale manufactures, as for example, of beer
bottles with distinctive marks. The usual labelling of such bottles, which must be
repeated with each filling, can with advantage be replaced by an impregnation,
which does not leave the mark less clear but, on the contrary, makes it nearly
indestructible by chemical or mechanical action.
The process is carried out as follows :-
An amount is taken, for example of 100 grammes of 40 per cent. silicate of
sodium or potassium and 50 grammes of 7 per cent. caustic soda in a glass vessel,
in which the mixture is allowed to stand until the caustic soda is dissolved into the
silicate of sodium or potassium.
The solution is then put into a bottle, corked and well shaken, when the bottle
is put in warm water and allowed to remain therein long enough for the solution to
clear. The latter is then ready for use. A rubber plate, on which the drawing
to appear coloured on the glass, porcelain or enamel surface is shown in relief, is
covered with a roll which takes up the fluid, and the moistened rubber plate is then
pressed on the object treated, which is effected for instance, in the case of bottles, by
their being rolled on the rubber plate. The still colourless imprint, retained on the
glass bottle, is then covered with any required colour powder, and the latter rubbed
in by means of small pads. Bronze powders in several shades are specially suitable
and give, particularly on green glass, very effective pictures. It is understood that
the colour powder could be added to the clear solution before the imprint is made
so that a coloured print is made direct. If pictures in several colours are to be
produced, this is most efficiently done by rubbing in the dry colour powder, when,
by the use of suitable patterns, those parts of the picture which are not to receive
the same colour may be covered. The last part of the process consists in drying
the objects treated, or the pictures on them. For this purpose they must be raised
to a temperature of 40°-50° Reaumur. There is, consequent to this, a complete
binding of the substance of the print with the under layer or rather the latter is
impregnated with the first, and even after removal of the layer of colour, which
can only be effected by the use of strong mechanical means, such as cutting by
chisel, the imprint of the picture in dark shade on a light ground still remains.
An attempt to remove the coloured picture by washing in cold or boiling water or
in acids has in practice been absolutely without success.
ย
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
A process by which pictures, letters and the like in one or more colours may be
produced on objects made of glass, porcelain, enamel and the like, consisting in
such objects being impregnated with a solution of two parts by weight of 40 per
cent. silicate of sodium or potassium and 1 part by weight of 7 per cent. caustic

page_text: soda, effected by pressing a stamp moistened with the solution, on the surface to be
treated, with colour powder added to the solution or rubbed in by means of small
pads after the imprint of the latter, whereupon the objects so prepared are submitted
to a temperature of 40°-50° Reaumur for the purpose of drying substantially as
described.
Dated this 17th day of July 1893.
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.