IMPROVEMENTS IN PIIOTO- GRAPHY RELATING TO THE PRODUCTION OF PHOTOGRAPHIC PICTURES ON WOVEN FABRICS
Year: 1877

page_text: LETTERS PATENT to Charles Denton Abel, of Southampton Buildings, in
the County of Middlesex, for the Invention of "IMPROVEMENTS IN PIIOTO-
GRAPHY RELATING TO THE PRODUCTION OF PHOTOGRAPHIC PICTURES ON
WOVEN FABRICS." A communication from abroad by William Winter, of
Prague, in the Empire of Austria.
Sealed the 8th June 1877, and dated the 31st March 1877.
Sealed the 8th June 1877, and dated the 31st March 1877.
PROVISIONAL SPECIFICATION left by the said Charles Denton Abel at the
Office of the Commissioners of Patents on the 31st March 1877.
CHARLES DENTON ABEL, of Southampton Buildings, in the County of Middlesex.
"IMPROVEMENTS IN PHOTOGRAPHY RELATING TO THE PRODUCTION OF PHOTOGRAPHIC
PICTURES ON WOVEN FABRICS." A communication from abroad by William Winter,
of Prague, in the Empire of Austria.
The object of this Invention is to produce magnified positive photographs on
woven fabrics, such as linen, cotton, silk, or wool, and with the use of iodide or
chromide of silver.
The process consists essentially in impregnating the woven fabric with iodide or
chromide of silver, and thereby making it so sensitive to light that from a negative
plate of about eight square inches a magnified positive photograph of up to more
than forty square feet may be produced on the said woven fabric.
When electric light is employed the positive photograph may be produced in from
one to four minutes.
The iodides and chromides are in general use for producing negatives, but hardly
at all for positives; and although many attempts have been made to utilise the sen-
sibility of these salts for the purpose of rapidly producing magnified photographs on
paper, these experiments have nearly always remained futile.
The proportions of the chemicals to be used may vary, not only according to tem-
perature, but also according to the density and material of the woven fabric, so that
in the case of lower temperatures and denser woven fabrics, which do not so easily
absorb fluids, the solutions must be made stronger, and iodides must be used in pre-
ference to chromides.

page_text: By way of example there shall now be described the proportions that may be used
at a temperature of from twenty to twenty-three degrees centigrade, and with linen
or cotton fabrics of average density and fineness; this description will serve as a
measure for the possible variations under the previously mentioned circumstances.
The woven fabrics must be first freed from all chemical impurities, and the subse-
quent operations may then follow in the manner now to be described.
First. The Treatment with Chromides.-The woven fabric is passed through a
solution composed of four parts by weight of chromide of potassium, one part of
chromide of cadmium, and two hundred and forty parts of water, so as to be equally
wet on both sides, and is then hung up to dry.
Secondly. The Treatment with Silver.-The dried woven fabric is passed through
a solution of four parts by weight of nitrate of silver, one part of citric acid, and one
hundred and forty parts of water, and again dried.
Thirdly. The Exposure to Light. For this purpose it is generally preferable to
use electric light, which may be produced by a dynamo-electric apparatus. In all 1
other respects the proceedings are the same as in the production of magnified photo-
graphs by means of the solar camera. The sensitised woven fabric is exposed to the
light until the positive photograph is distinctly visible thereon. The time necessary
for this exposure depends upon the size and strength of the negative; generally one
to four minutes are required.
Fourthly. The Development.-A solution composed of ten parts of pyrogallic acid,
forty-five parts of citric acid, and four hundred and ten parts of water is put into a
large flat pan, and the woven fabric is left in this solution until the photographic
picture or print thereon is sufficiently developed.
The remaining proceedings are as usual in photographic processes. The picture is 2
well washed and then toned and fixed, and finally again well washed.
It is evident that, without departing from the substance of this Invention, other
sources of light and other iodides and chromides may be used for producing mag-
nified photographic pictures or prints on woven fabrics.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by a
the said Charles Denton Abel in the Great Seal Patent Office on the 29th
September 1877.
CHARLES DENTON ABEL, of Southampton Buildings, in the County of Middlesex.
"IMPROVEMENTS IN PHOTOGRAPHY RELATING TO THE PRODUCTION OF PHOTOGRAPHIC
PICTURES ON WOVEN FABRICS." A communication from abroad by William Winter,
of Prague, in the Empire of Austria.
The object of this Invention is to produce magnified positive photographs on
woven fabrics, such as linen, cotton, silk, or wool, and with the use of iodide or
chromide of silver.
The process consists essentially in impregnating the woven fabric with iodide or
chromide of silver, and thereby making it so sensitive to light that from a negative
plate of about eight square inches a magnified positive photograph of up to more
than forty square feet may be produced on the said woven fabric.
When electric light is employed the positive photograph may be produced in from
one to four minutes.
The iodides and chromides are in general use for producing negatives, but hardly
at all for positives; and although many attempts liave been made to utilise the sen-
sibility of these salts for the purpose of rapidly producing magnified photographs on
paper, these experiments have nearly always remained futile.
The proportions of the chemicals to be used vary, not only according to tem-
perature, but also according to the density and material of the woven fabric, so that
in the case of lower temperatures and denser woven fabrics, which do not so easily

page_text: absorb fluids, the solutions must be inade stronger, and iodides must be used in pre-
ference to chromides.
By way of example there shall now be described the proportions that may
be used at a temperature of from twenty to twenty-three degrees centigrade, and
with linen or cotton fabrics of average density and fineness; this description will
serve as a measure for the possible variations under the previously mentioned
circumstances.
The woven fabrics must be first freed from all chemical impurities, and the subse-
quent operations may then follow in the manner now to be described.
First. The Treatment with Chromides.-The woven fabric is passed through a
solution composed of 4 parts by weight of chromide of potassium, 1 part of chromide
of cadmium, and 240 parts of water, so as to be equally wet on both sides, and is
then hung up to dry.
Secondly. The Treatment with Silver.-The dried woven fabric is passed through
a solution of 4 parts by weight of nitrate of silver, 1 part of citric acid, and 140 parts
of water, and again dried.
Thirdly. The Exposure to Light-For this purpose it is generally preferable to
use electric light, which may be produced by a dynamo-electric apparatus. In all
other respects the proceedings are the same as in the production of magnified photo-
graphs by means of the solar camera. The sensitized woven fabric is exposed to the
light until the positive photograph is distinctly visible thereon. The time necessary
for this exposure depends upon the size and strength of the negative; generally one
to four minutes are required; but it may be added that although the use of electric
light is generally preferable, other artificial light or the solar rays may be used in
the process.
Fourthly. The Development.-A solution composed of 10 parts of pyrogallic acid,
45 parts of citric acid, and 410 parts of water is put into a large flat pan, and the
woven fabric is left in the solution until the photographic picture or print thereon is
sufficiently developed.
The remaining proceedings are as usual in photographic processes. The picture is
well washed, then toned and fixed, and finally again well washed.
It is evident that, without departing from the substance of this Invention, other
sources of light and other iodides and chromides may be used for producing mag-
nified photographs on woven fabrics.
Having thus described the nature of this Invention and in what manner the same
is to be performed, as communicated to me by my foreign correspondent, I claim,-
First. Woven fabrics provided with magnified positive photographs, essentially as
described.
Second. The process for producing magnified positive photographs on woven
fabrics, essentially as described.
Third. The process for producing magnified positive photographs on woven fabrics
by the use of iodide or chromide of silver, essentially as described.
Fourth. The use of electric light for producing magnified positive photographs on
woven fabrics when these are impregnated with iodide or chromide of silver, essen-
tially as described.
In witness whereof, I, the said Charles Denton Abel, have hereunto set my
hand and scal, this Twenty-seventh day of September, in the year of our
Lord One thousand eight hundred and seventy-seven
CHA³. D. ABEL. (L.S.)