A Process for Photographing by means of Organic Compounds.
Year: 1890

page_text: Date of Application, 13th May, 1890
Complete Specification Left, 12th Mar., 1891-Accepted, 18th Apr., 1891
PROVISIONAL SPECIFICATION.
A Process for Photographing by means of Organic Compounds.
We, ARTHUR GEORGE GREEN, of Thistlewaite Road, Lower Clapton, London,
N.E., CHARLES FREDERICK CROSS and EDWARD JOHN BEVAN, both of 4, New
Court, Carey Street, W.C., all Research and Consulting Chemists, do hereby
declare the nature of this invention to be as follows:-
manner.
Our invention relates to the production of designs on paper, textures or other
suitable surfaces by means of organic compounds, which we effect in the following
We sensitise the material by impregnating it with a diazo compound
produced by the action of nitrous acid on a primary aromatic amine, or by impreg-.
nating the material first with an amine compound and diazotising the amine in situ
by the action of nitrous acid. One of the amine compounds best suited for the
purpose is that commercially know as "primuline." We expose the material thus
sensitised to the action of light according to any known process of photography,
and then we treat with an amine or a phenol or a sulphonic or carboxylic derivative
thereof. The result is that the material is coloured according to the less or greater
action that the light has on the diazo compound with which it was in the first
place treated, and according to the particular amine or phenol or compound after-
wards employed.
The colours produced may be varied or toned by employing at various stages of
the process, metallic salts, mordants or colouring matters.
Dated this 13th day of May 1890.
ABEL & IMKAI,
Agents for the Applicants.
COMPLETE SPECIFICATION.
A Process for Photographing by means of Organic Compounds.
We, ARTHUR GEORGE GREEN, of 5, Thistlewaite Road, Lower Clapton,
London, N.E., CHARLES FREDERICK CROSS and EDWARD JOHN BEVAN, both
of 4, New Court, Carey Street, W.C., all Research and Consulting Chemists, 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:-
Our invention relates to the production of designs on paper, textures or other.
suitable receptive surfaces by means of organic compounds.
It is a property of the diazo compounds, generally, to combine with most phenols
and amines producing colouring-matters; it has been found however that by the
action of light many of these compounds undergo a change or decomposition by
which they lose this property. Upon these facts we base our photographic process
for the production of coloured designs upon textile materials, paper, glass, xylonite,
etc., which we carry out as follows:--We sensitise the surface by application of a
diazo-compound or we form the diazo-compound in situ by applying to the surface
the corresponding amine or amido-acid, and subsequently treating with nitrous acid.
We then expose the surface thus sensitised to the action of light under the object or
design of which it is required to obtain an image; it may be a natural object, a photo-
graphic positive, or any painted, printed or photographic or other design upon trans-
parent material. After a sufficient exposure, the picture is developed by immersion in
a suitable solution of an amine or phenol or the sulphonic or carboxylic acids thereof.
The diazo-compounds which are most suitable for our purpose are those derived.

page_text: корпет and its alkуi derivatives.
(g) Phenylene and tolylene meta-diamines and their alkyl derivatives.
(h) Resorcin and its sulphonic and carboxylic acids.
(i) Phenol, cresol and pyrogallol.
() Salicylic acid, and oxy-naphthoic acids.
The amines and amido acids are employed in slightly acid solution, the phenols
and oxy-acids in alkaline solution and the amido-phenols either in alkaline or
slightly acid solution.
As an example of the method of carrying out our invention we make take the
production of a coloured design upon a textile material, paper or other fabric by
means of the diazo-compound of "primuline."
The fabric is first dyed with primuline from a hot solution or is coated or printed
with primuline. After washing, the fabric is immersed for about half a minute in a
bath of nitrous acid prepared by acidifying with sulphuric or hydrochloric acid a
weak solution say about per cent. of sodium nitrite in cold water. The fabric now
holding diazotised primuline is washed and exposed to light, either in a wet or dry
state under the object or design to be printed. After sufficient exposure (as can be
ascertained by a trial exposure of a portion) the fabric is passed through a solution
of a suitable phenol or amine which may, for example, be
For red an alkaline solution of beta-naphthol,
For orange an alkaline solution of resorcin,
For purple-a solution of alpha-naphthylamine hydrochloride.
'If it is required to produce the design in more than one colour, the respective
developing solutions are applied locally.
As another instance of the application of our process we may describe the pro-
duction of transparent pictures upon glass by means of a sensitised gelatine film.
One hundred parts of hard gelatine are dissolved in water together with from I to
10 parts of primuline, according to the depth of colour desired, and part of chrome
alum.
The glass is evenly coated with the warm solution and the film is left to set.
The diazotisation, washing, exposure and final development are carried out in
exactly the same way as described in the previous example for fabrics.
It may in some cases be advisable to use various agents such as metallic salts,
mordants, or colouring matters for increasing the sensitiveness of the 'diazo

page_text: compound, clearing the back-ground, fixing the colouring matter or otherwise
heightening or toning the effect, or improving the result.
Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed, we declare that what
we claim is :-
The herein described process of photographic printing by sensitising a suitable
receptive surface with a diazo compound, exposing the sensitised surface to photo-
graphic action, and developing the design or picture by treatment with a suitable.
amine, phenol, amido-phenol, or with their sulphonic or carboxylic acids.
Dated this 12th day of March 1891.
ABEL & IMRAY,
Agents for the Applicants.