An Improved Process for the Production of Photographs in Natural Colors upon Paper or other Flexible Support.
Year: 1899

page_text: Date of Application, 27th Feb., 1899
Complete Specification Left. 27th Nov., 1899-Accepted, 30th Dec., 1899
PROVISIONAL SPECIFICATION.
An Improved Process for the Production of Photographs in Natural
Colors upon Paper or other Flexible Support.
I, GUSTAV SELLE, of Brandenburg, on the Havel, in the Empire of Germany,
Physician, do hereby declare the nature of this invention to be as follows:-
It is well known that in 3 colour photography a given object is photographed
3 times, first by means of a negative placed behind a blue filter, secondly by a
negative placed behind a green filter, and thirdly by a negative placed behind a
red filter. From these negatives three positives are produced coloured respec-
tively yellow, red, and blue; when these are exactly superimposed the result is
a photographic reproduction in colour of the original object.
Many attempts have been made to apply the principle of the above to producing
coloured photographs without transference of films but hitherto the results have
not been satisfactory. But by my invention I am able to produce direct on paper
such photographs, in an easy manner ensuring a constancy of results. This inven-
tion I will now proceed to describe taking as example the bichromated collodion
process for the production of photograph required.
I take a rigid waterproof plane of desired size for instance, a glass plate
one side of which I coat around the edges to a width of say quarter of an inch
with a solution of gelatine of, for instance, 10%. I now take a sheet of paper
one side of which at least should be covered with a waterproofing material and
after cutting it to the size of the glass plate I place it on top of the latter
applying pressure so that the edges of the paper may adhere firmly to the
gelatine on the glass care being had to expel any air from between the paper and
the glass plate. If a non waterproof paper is used then the latter should be
cut slightly smaller than the glass and should be placed for a few minutes in water
prior to being put on the glass support. The paper being quite dry and adhering
to the glass plate I cover it with a thin layer of impervious and as transparent
as possible material, for instance, collodion. On this film when dry I spread
a very thin layer of plain bichromated gelatine and allow it to dry. I then
expose this plate to the action of light under either of the 3 negatives, say for
instance, the red negative. The transferring of the image from the negative
to the paper beneath it, i.c. the printing, having been accomplished, the plate is
washed in cold water and is then placed in a fluid bath consisting of a solution
of say 5% methyl blue until the image is fully developed. The plate is then
taken out of the bath and allowed to dry. When quite dry the aforesaid operation
of coating with collodion and bichromated gelatine is repeated. The plate is
then printed under the green negative washed and placed in a bath consisting
of say a 3% solution of fuchsin (red) until the image is fully developed. I thus
have the red image on top of the blue image. The plate after drying is covered
for the third and last time with a collodion and bichromated gelatine layer, it
is then printed under the blue negative, washed and developed in a bath con-
sisting for instance of a 7 and a half % of solution of helianthin (yellow) when

page_text: dry the photographic print on paper is finished; it is then cut all round within
the borders of gelatine when it will come clear off the glass and can be mounted
like any ordinary photograph. The superimposition of the 3 negatives during
the 3 printings is easily accomplished by holding the plate up to the light and
making the contours on the negative fit, i.e. cover the contours of the image on
the plate beneath it, the plate and negative are then during printing held together
by means of strong spring clips instead of being placed in a printing frame. In
case where thick very opaque paper is used it is desirable as is done in multi
color printing to make corresponding register marks on the negatives subsequently
duplicated on the positives which will remove the difficulty of obtaining a true
register.
Dated this 07th day of Tahmame 1900
HERBERT HADDAN & Co.,
Agents to Applicant,
18, Buckingham Street, Strand, W.C., London.
.
An Improved Process for the Production of Photographs in Natural
Colors upon Paper or other Flexible Support.
GUSTAV SELLE, of Brandenburg, on-the-Havel, in-the-Empire-of-Germany,
Physician, 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:-
It is well known that in 3 color photography a given object is photographed
times, first by means of a negative placed behind a blue filter, secondly by a
negative placed behind a green filter, and thirdly by a negative placed behind a
red filter. From these negatives three positives are produced colored respec-
tively yellow, red, and blue; when these are exactly superimposed the result is
a photographic reproduction in color of the original object.
Many attempts have been made to apply the principle of the above to producing
colored photographs without transference of films but hitherto the results have
not been satisfactory, but by my invention I am able to produce direct on paper
such photographs in an easy manner ensuring uniformity of results. This inven-
tion I will now proceed to describe taking as example the bichromated collodion
process for the production of the photograph required.
I take a rigid waterproof plane of desired size, for instance, a glass plate,
preferably somewhat larger than the finished print is to be, by at least half an
inch each way. One surface of this plate I coat around the edges to a width
of say, a quarter of an inch with a solution of gelatine of, for instance, 10 per
cent. strength. I now take a sheet of paper one side of which at least, should
be covered with a waterproofing material and after cutting it to the size of the
glass plate I place it on top of the latter (a waterproofed side being uppermost)
applying pressure so that the edges of the paper may adhere firmly to the gelatine
on the glass, care being had to expel any air from between the paper and the
⚫glass plate. If a non-waterproof paper is used, then the latter should be cut
slightly smaller than the glass and should be placed for a few minutes in water
prior to being put on the glass support. The paper being quite dry and adhering
to the glass plate I cover it with a thin layer of an impervious material, which
is as transparent as possible for instance, collodion. On this film when dry I
spread a very thin layer of plain bichromated gelatine and allow it to dry. I

page_text: then expose this plate to the action of light under either of the three negatives,
say, for instance, the "red" negative. The transferring of the image from the
negative to the paper beneath it, i.e. the printing having been accomplished,
the plate is washed in cold water and is then placed in a bath consisting of the
appropriate solution, of, for example, (if the "red" negative was used first) 5 per
cent. methyl blue, until the image is fully developed. The plate is then taken
out of the bath and allowed to dry. When quite dry the aforesaid coating opera-
tions with collodion and bichromated gelatine (which are here termed " sensi-
tizing") are repeated. The plate is then printed under another negative for
instance, the " green" negative, then washed and placed in a bath consisting of
the appropriate solution, say, a 3 per cent. solution of fuchsin (red) until the
image is fully developed. I thus have the red image on top of the blue image.
The plate after drying is sensitized for the third and last time; it is then printed
under the "blue" negative, washed and developed in a bath consisting for
instance, of a 7 and a half per cent. solution of helianthin (yellow). When dry
the photographic color print on paper is finished; it is then cut all round within
the edges of the gelatine, which was applied to the glass as first mentioned. The
paper carrying the print will then come clear off the glass and can be mounted
like any ordinary photograph. The superimposition of the 3 negatives during
the 3 printings is easily accomplished for the second and third negatives by
holding the plate up to the light and making the contours on the negative coin-
cide with the contours of the image on the plate beneath it, the plate and negative
are then during printing held together by means of strong spring clips instead
of being placed in a printing frame. In case where thick opaque paper is used
it is desirable, as is done in multi-color printing, to make corresponding register
marks on the negatives, which will become subsequently reproduced on the
positives and serve to remove the difficulty of obtaining a true register.
By mounting the paper on an inextensible and incompressible support in this
manner it is not subject to alteration in size locally or wholly during the process,
or at least it is not found that the paper after each drying has shrunk so that
the next printing will not register with the previously developed image as is
the case when no such support is employed or where the paper is transferred
from one support to another during the process or in the intervals of the process.
The support must be such as will keep out the water from the back of the
paper unless the paper is fully waterproofed on both sides. In practice it will
be found advisable to use glass for the support, and in such case it is not necessary
to waterproof both sides of the paper
Moreover the method of attaching the paper to the support herein before
described which leaves that part of the paper on which the printing is done
unfastened except by its margins, enables it to be simply removed when finished
by cutting it away from the edges which remain adhering to the support until
they are subsequently cleaned off the latter. when it is required for use again.
It will be readily understood that other materials besides paper may be employed
in the same way, for example, textile fabrics.
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:
1. The process for production of photographs in natural colors upon paper or
other flexible material, consisting in mounting the same upon a non-extensible
and non-compressible plane support by attaching the same by an adhesive round
its margins only, coating said paper or material with waterproof material unless
previously done, carrying out thereon the operations of sensitizing photographic
printing and developing for one of the negatives, repeating said operations of
sensitizing, printing and developing successively for the other negatives respec-
tively without moving the paper or material from its support and lastly removing

page_text: the material from its support by cutting it within the adhering margins, sub-
stantially as described.
2. The process for production of photographs in natural colors. upon paper or
other flexible material, consisting in mounting the same upon a non-extensible
and non-compressible plane support, for example, a sheet of glass by gelatine
round its margins, employing three times successively thereon the process of
sensitizing, drying, printing under the respective negative, washing in cold water,
déveloping in the corresponding color bath and drying, and lastly removing the
paper or other flexible material from its support by cutting it within the adhering
margins.
3. Carrying out the processes claimed in the preceeding claims with the solu-
tions herein mentioned substantially, as described.
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Dated this 27th day of November 1899.
HERBERT HADDAN & Co.,
Agents to Applicant,
18, Buckingham Street, Strand, London