A NEW OR IMPROVED PROCESS FOR PRODUCING PICTURES ON GLASS, STONE, METAL AND OTHER MATERIALS
Year: 1882

page_text: LETTERS PATENT to Herbert John Haddan of Kensington, Middlesex for an
invention of A NEW OR IMPROVED PROCESS FOR PRODUCING PICTURES ON
GLASS, STONE, METAL AND OTHER MATERIALS A communication to him from
abroad by Edouard Godard, of Paris, France
PROVISIONAL SPECIFICATION left by the said Herbert John Haddan at the
Office of the Commissioners of Patents on the 15th May 1882.
HERBERT JOHN HADDAN, of Kensington, Middlesex, "A NEW OR IMPROVED
PROCESS FOR PRODUCING PICTURES ON GLASS, STONE, METAL AND OTHER MATERIALS,"
a communication to me from abroad by Edouard Godard, of Paris, France.
This Invention consists in a new process for reproducing and fixing images on
glass, metal, prepared canvas, wood, stone, and other materials. The original is
drawn on white or blueish paper and a sheet of glass placed on the backside of the
paper previously impregnated with petroleum for making it transparent. The
glass or other surface on which the image is to be produced, is coated with a
sensitive solution of bichromate of ammonia, and glucose, or dextrin prepared and
applied in a dark chamber or in non-actinic light, after which the coating is dried
at a temperature of 50 to 60 degrees Centigrade. The sheet of glass with the
original is then fixed in a photographic copying frame, so as to place the prepared
surface in contact with the original picture, and the frame is exposed to light,
behind a window at a temperature from 14 to 18 degrees Centigrade. The time
necessary for exposure can be ascertained by taking out one of the many pieces of
glass, applying to the sensitive surface a vitrifiable colour, and observing whether
the colour adheres well. If the colour adheres but slightly to the dark shady
portions of the image, the exposure has been too long, and the process must be
recommenced, if on the contrary the colour adheres too well, the exposure has not
been sufficient, the copying frames must be closed again and the exposure continued.
When the frame has been sufficiently exposed it is taken into the dark room, the

page_text: sensitized pieces of glass laid on a plate of glass or marble with the sensitive
surface turned upward, and the previously prepared vitrifiable colour strewed over
it by means of a few light strokes of a brush. This powder does not adhere to the
parts of the picture fully exposed to light, but adheres only to the more or less
shady portions of the picture. The colour is applied to the surface until the image
has appeared as dark as the original. Afterwards I take 1000 grammes of wood-
spirit, such as is generally used in photography, add 30 to 40 grammes of nitric
acid, and dip all prepared pieces of glass into this bath, leaving them afterwards
to dry. This bath has the object to remove the coating of bichromate so as to
allow the colour to adhere to the glass from which it had been separated by the
layer of glucose and bichromate, which would prevent the vitrification. The
application of variously coloured enamels, and the heating are then effected as in
ordinary glass-painting.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent and of
an Order of the Lord Chancellor filed by the said Herbert John Haddan in
the Great Seal Patent Office on the 22nd November 1882.
12
HERBERT JOHN HADDAN, of Kensington, Middlesex "A NEW OR IMPROVED
PROCESS FOR PRODUCING PICTURES ON GLASS, STONE, METAL AND OTHER MATERIALS
a communication to me from abroad by Edouard Godard, of Paris, France
This invention has for its object to reproduce images and drawings by means of
vitrifiable colours on glass of any shade or colour.
This process may also be applied to wood, marble and other stone, on canvas
or paper prepared for oil-painting and to other solids having polished surfaces, for
instance earthenware, porcelain and copper.
The original drawings or images should be well executed and drawn on white or
preferably bluish paper similar to paper used for ordinary drawings.
In the patterns for glass painting by this process one marks the place to be
occupied by the lead, before cutting the glass to suit the various shades which
compose the colour of a panel, as is usually done in this kind of work, the operation
changes only when the glass cutter hands these sheets over to the man who under-
takes the painting.
The sheets of glass are cut according to the lines of the drawing and after being
well cleaned, they are placed on the paper on the places for which they have been
cut out.
If the window to be stained is of large size and consists of several panels, only
one panel is proceeded with at the time.
The glass is laid on the reverse side of the paper (the side opposite to the
drawing) the latter having been made transparent by saturating it with petroleum.
This operation also serves to fix the outlines of the drawing more distinctly and
to give more vigour to the dark tone of the paper.
When the paper is thus prepared and the sheets of glass each in its place they
are coated by means of a brush with a sensitizing solution on the side which comes
into contact with the paper.
This coating should be as thin and as uniform as possible on the surface of the
glass. For more perfectly equalizing the coating a second brush is used.
The sensitizing solution which serves to produce the vitrifiable image, is pre-
pared as follows: As much Bichromate of ammonia is dissolved in water till
the latter is saturated, 5 grammes of powdered dextrin or glucose are then dissolved
in 100 grammes of water, to either of these solutions I add 10 per cent. of the
solution of Bichromate as described above, and filter the resulting mixture.
The coating of the glass takes place immediately afterwards in a dark room the
coated sheets are then subjected to a heat of 50 or 60 degrees in a small hot
chamber, where they are laid one after the other on a wire grating situated
35 centimetres above the bottom.
Care should be taken not to introduce the glass under treatment into the hot
chamber before the required degree of heat has been obtained.
A few seconds are sufficient to dry each sheet, and the wire grating should be
large enough to allow of the dried glass being laid in rows on one side where the
heat is less intense.
For the reproduction of the pictures or images a photographic copying frame of
the size of the original is used.
A stained glass window being for greater security generally divided into

page_text: "
If
different panels the size of one panel is seldom more than one square metre.
the picture to be reproduced should be larger in size than any available copying
franie, the prepared glass sheets are laid between too large sheets of plate glass
and part after part is proceeded with by sliding the original between the two
sheets.
A photographic copying frame however is always preferable, as it presses the
glass sheets better against the original.
The original drawing is laid flat on the glass of the frame.
The lines where the lead is to connect the respective sheets of glass, are marked
on the drawing with blue or red pencil.
The prepared sheets of glass are then placed one after the other on the original
in their respective places so that the coated side comes in contact with the said
original.
The frame is then closed.
It should be borne in mind that the latter operations must be performed in the
dark room.
The closed frame is now exposed to light.
If the operations are performed outdoors the frame is laid flat so that the light
falls directly on it; if indoors, the frame is placed inclined behind a window, so that
it may receive the light in front.
The time necessary for exposing the frame depends upon the light and the
temperature, for instance if the weather is fine and cloudless and the temperature
from 16 to 18 degrees it will require from 12 to 15 minutes.
It will be observed that the time of exposure also depends on the thickness of
the paper used for the original. If, however, the weather is dark, it requires
from 30 to 50 minutes for the exposure in which case several frames may be
proceeded with at the same time, which saves time, for while one frame is exposed
another one may be prepared and so on.
It will be observed that if the temperature is above 25 degrees the sheets of glass
should be kept very cool and be less dried, otherwise, when exposed the sheets are
instantly metallised and the reproduction cannot take place.
The same inconvenience takes place if the temperature is beneath 5 degrees.
In this case the sheets should be kept warm and care should be taken not to
expose the frame to the open air, but always behind a glass window at a temperature
of from 14 to 18 degrees. The time necessary for the exposure can be ascertained
by taking out one of the many pieces of glass, applying to the sensitive surface a
vitrifiable colour, and observing whether the colour adheres well. If the colour
adheres but slightly to the dark shady portions of the image, the exposure has
been too long and the process must be recommenced; if, on the contrary, the colour
adheres too well, the exposure has not been sufficient the frames must be closed
again and the exposure continued.
To save time and trouble the time necessary for the exposure may be ascertained
by first proceeding with a small frame containing only two small sheets of prepared
glass when the exact time for exposure can be ascertained and operations with the
large frames can safely commence.
When the frame has been sufficiently exposed it is taken into the dark room, the
sensitized pieces of glass laid on a plate of glass or marble with the sensitive surface
turned upward and the previously prepared vitrifiable colour strewed over it by
means of a few light strokes of a brush.
This powder does not adhere to the parts of the picture fully exposed to light
but adheres only to the more or less shady portions of the picture. This operation
develops on the glass the image as it is on the paper.
I then add 30 to 40 grammes of nitric acid to 1000 grammes of wood-spirit such
as is generally used in photography and dip all prepared pieces of glass into this
bath, leaving them afterwards to dry.
If the bath becomes of a yellowish colour the same must be renewed.

page_text: This bath has for its object to remove the coating of bichromate, so as to allow
the colour to adhere to the glass from which it has been separated by the layer of
glucose and bichromate which would prevent the vitrification.
The bath has also for its object to render the light parts of the picture perfectly
pure, and capable of being easily retouched or painted by hand.
The application of variously coloured enamels, and the heating are then effected
as in ordinary glass painting.
The same process may be applied to marble, wood, stone, lava, canvas prepared
for oil painting, earthenware, pure or enamelled iron. The result is the same in all
cases and the process is the same as with glass with the difference only that the
above named materials are not dipped into the bath, but the liquid is poured over
the objects after the latter have been placed in an inclined position.
Having now described the invention as communicated to me by my foreign
correspondent I wish it to be understood that I do not bind myself to the exact
proportions of materials for the sensitizing solution as stated in the above
specification, and that the details of the process may otherwise be varied without
departing from the principle of this invention,
CLAIM,
1. The process of producing images in vitrifiable colours on glass, wood, marble,
O metal, and other surfaces, substantially as described.
In Witness whereof I the said Herbert John Haddan have hereunto set my
hand and seal this twenty-second day of November A.D. 1882.