which will the of Fire.
Year: 1885

page_text: which will Withstand the Action of Fire.
I THOMAS BOLAS of 8 Grove Terrace Chiswick Middlesex Analytical Chemist
do hereby declare the nature of my invention for DECORATING OR IMPRINTING
DEVICES UPON GLASS METAL STONE POTTERY, ENAMEL ASBESTOS SLABS OR SHEETS
OR OTHER MATERIALS WHICH WILL WITHSTAND THE ACTION OF FIRE, to be as
follows:-
My invention consists in the preparation of a tissue consisting of a gelatinous
mixture spread upon paper or other analogous material and the use of this tissue
in the manner indicated below.
.
To prepare the tissue I dissolve gelatine in water generally with the addition of
sugar gum and of a metallic substance or compound which will serve as a vitrifiable
or fire standing pigment and I spread this gelatinous solution or mixture upon
paper or its equivalent so as to form a thin coating-The gelatinous conting is
then made sensitive to light by the addition of a soluble bi-chromate by preference
the bichromate of potassium ammonium or sodium-this addition being made by
moistening or wetting the tissue with a solution of the soluble bichromate and
allowing the tissue to dry-In some instances I prefer to add the soluble bichromate
to the gelatinous solution or mixture before the paper is coated.
The exposure of the tissue to light is effected by one of the methods of exposure
well known to Photographers that is to say it may be exposed under a transparent
or translucent device or a luminous image formed by a lens may be projected upon
it. The result of exposure to light is to render the gelatine insoluble in those parts
corresponding to the more transparent portions of the transparent or translucent
device or in those parts upon which light has acted most freely. I next immerse
the exposed tissue in water so as to make it flaccid or pliable and lay it with the
gelatinous side downwards against the surface to be decorated. I establish contact
and adhesion by gentle pressure; this pressure may if the surface of the article to
be decorated is flat be advantageously exercised by gently stroking the back of the
tissue with a "squeegee or squeezee that is to say a strip of india rubber
mounted in a rigid handle; when on the other hand the surface of the article to
be decorated is curved or irregular I prefer to make a reverse or counter mould of
"
"

page_text: plaster gutta percha or other suitable material and I use this counter mould in
order to establish contact between the tissue and the surface to be decorated. The
object bearing the exposed tissue is next exposed to the action of warm water either
by immersion or by causing the water to How over the part to which the tissue
adheres. In a very short time the gelatine or the gelatinous compound becomes so
far softened by the warm water that the paper or backing of the tissue can be
stripped off, leaving that part of the gelatine which was rendered insoluble by the
action of light on the surface to be decorated. The action of the warm water is
allowed to continue until all gelatine which is easily soluble is removed and the
device is clear and distinct; after which the article is rinsed in cold water and
allowed to dry preparatory to the baking or firing. Under certain conditions it is
necessary to subject the image to some intermediate processes before firing. The
object of these intermediate processes being either to increase the amount of
metallic substance or compound which will serve as a vitrifiable or fire standing
pigment or to add such metallic substance in the event of none having been used
in compounding the original gelatinous solution or compound-The following may
be cited as examples of the methods of adding the metallic substances at this stage.
1. The gelatinous image may be allowed to remain in contact with a solution of
an alkaline permanganate, whereby oxide of manganese is deposited upon it.
2. The gelatinous image may be allowed to remain in contact with a compound
solution made by mixing a solution of a ferric salt with a solution of ferricyanide
of potassium whereby an iron compound is deposited upon the gelatine. The
deposition of the iron compound is in this case very materially assisted by exposure
to light.
3. In a similar way, solutions of gold silver palladium iridium uranium and
other metals may be used at this stage in order to charge the gelatine with a
metallic substance capable of acting as a fire standing pigment or to increase the
amount of metallic substance present.
4. The object bearing the gelatinous device is rinsed and dried but the drying
action is not allowed to go so far as to dry the gelatine. Over the moist gelatine
suitable metallic substances or compounds capable of acting as fire standing pigments
are now dusted, the excess being wiped off with a soft brush or its equivalent. As
examples of the metallic substances which may be used at this stage I may cite
the above mentioned metals in a state of fine division, or their compounds. The
ordinary potters colours of commerce, whether for "overglaze " or " underglaze
may often be used with advantage.
"
The next and final stage in the process is to expose the article bearing the device
to a temperature sufficient to cause the gelatine to burn away and to leave the
metallic substance or vitrifiable pigment. For this purpose the objects are heated
to a sufficient temperature in a muffle or a potter's oven but in order to prevent
the blistering or sizzling up of the gelatine certain precautions should be taken.
A lump of cyanide of potassium may be placed in the muffle or oven and its
vapour serve to moderate the blistering tendency of the gelatine but I prefer to
inject into the muffle or the oven a fine spray of a solution of an alkaline salt.
The alkaline salts most useful are cyanide of potassium, carbonate of potassium,
borax and silicate of sodium. One other precaution is sometimes needed when
one wishes to obtain the devices with bright metallic lustre, or to obtain the red
colour characteristic of cuprous oxide when vitrified and this precaution is to
introduce a reducing gas or vapour into the muffle or oven. In this connection
hydrogen carburetted hydrogen or carbon monoxide may be mentioned as examples
of suitable reducing gases.

page_text: When it is intended to treat the image with a metallic preparation as described
in a subsequent part of this Specification, the metallic or vitrifiable pigment may
be wholly or partly omitted, and a little lamp black or other destructable pigment
may be added to give the mixture partial opacity.
"
The exposure of the tissue to light is effected by one of the methods of exposure
well known to photographers, that is to say it may be exposed under a transparent
or translucent device, or a luminous image formed by a lens may be projected upon
it. The result of exposure to light is to render the gelatine insoluble in those
parts corresponding to the more transparent portions of the transparent or trans-
lucent device or upon those parts on which light has acted most freely. I next
immerse the exposed tissue in water so as to make it flaccid, or pliable and then
lay it with the coated side downwards against the surface to be decorated.
I establish contact and adhesion by gentle pressure; if the surface of the article
to be decorated is.flat this pressure may be advantageously exercised by gently
stroking the back of the tissue with a "squeegee or "squeezee," that is to say a
strip of india rubber mounted in a rigid handle. When the surface of the article
to be decorated is curved or irregular I prefer to make a reverse or counter-mould
of plaster gutta percha, india rubber or other suitable material and I employ
pressure with the counter mould in order to establish contact between the tissue
and the surface to be decorated. The object bearing the exposed tissue is next
subjected to the action of warm water, either by immersion or by causing the
water to flow over the part to which the tissue adheres. In a short time the
gelatine or the gelatinous compound becomes so far softened by the warm water
that the paper or backing of the tissue can be stripped off, leaving that part of the
gelatine which was rendered insoluble by the action of light.
The action of the warm water is allowed to continue until all gelatine which is
easily soluble is removed and the device is clear & distinct; after which the article
is rinsed in cold water and allowed to dry preparatory to the baking or firing.
Under certain conditions it is necessary to subject the image to some intermediate
processes before firing; the object of such intermediate process being either to
increase the amount of metallic substance or compound which will serve as a
vitrifiable pigment or to add such metallic substance in the event of none having
been used in compounding the original gelatinous compound.
The following may be cited as showing how I add metallic substances at this
stage
1. The gelatinous image may be allowed to remain in contact with a solution of
an alkaline permanganate, whereby oxide of manganese is deposited upon it.
2. The gelatinous image is allowed to remain in contact with a compound
solution made by mixing a solution of a ferric.salt with a solution of red prussiate
of potash, whereby an iron compound is deposited upon the gelatine.
3. Solutions of gold, silver, palladium, iridium uranium and other metals may
also be used at this stage to charge the gelatine with a metallic substance capable
of acting as a fire-standing pigment.
4. The object bearing the gelatinous device is rinsed and dried, but the drying
action is not allowed to go so far as to dry the gelatinous image. Over the moist
gelatine, suitable metallic substances or compounds capable of acting as fire-
standing pigments are now dusted, the excess being wiped off with a soft brush or
its equivalent. As example of the metallic substances which may be used at this
stage I may cite the above mentioned metals in a state of fine division or their
compounds. The ordinary potters' colours of commerce, whether "overglaze". or
"underglaze" may also be used.
The next & final stage in the process is to expose the article bearing the device
to a temperature sufficient to cause the gelatine to burn away and to vitrify or fix
the pigment to the surface of the article to be decorated. The articles may be
heated in an ordinary potters oven or in a muffle, but in order to prevent the
blistering or sizzling of the gelatine, certain precautions should be taken.
A lump
of cyanide of potassium may be placed in the muffle or oven and its vapour serves

page_text: to moderate the blistering tendency of the gelatine, but I prefer to inject into the
muffle or the oven a fine spray of a solution of an alkaline salt. The alkaline
salts most useful are cyanide of potassium, borax and silicate of potassium or
sodium. One other precaution is sometimes needed, when one wishes to obtain
the devices with bright metallic lustre, or to obtain the red colour characteristic
of cuprous oxide, and this precaution is to introduce into the muffle or oven, a
reducing gas or vapour. In this connection, hydrogen, hydrocarbon gas or vapour
or carbon monoxide may be mentioned as suitable.
Having now particularly described and ascertained the nature of my inven-
tion and in what manner the same is to be performed I declare that what
I claim is
•
1. The use of a tissue in decorating surfaces substantially as described.
2. The use of counter-moulds substantially as described in connection with the
tissue.
3. The use of sprays of alkaline salts in the furnace or muffle & of cyanide of
potassium substantially as described.
4. The use of reducing gases or vapours in the furnace or muffle, substantially as
described.