Improvements in Photographic Printing Paper.
Year: 1895

page_text: Date of Application, 27th Nov., 1895
Complete Specification Left, 27th July, 1896-Accepted, 12th Sept., 1896
PROVISIONAL SPECIFICATION.
Improvements in Photographic Printing Paper.
I, GUSTAV KOPPMANN, Photographer, Hamburg, Billhörner Röhrendamm 54
do hereby declare the nature of this invention to be as follows:-
It is a wellknown fact that the albuminized papers used for photographic
positives loose their beautiful rose or bluish tint after a short time. Hitherto the
proceeding consisted in mixing the corresponding colour solution with the albumen
covering the paper with this mixture. The colours used are the little light-proof
aniline colours mixing perfectly with the albumen.
The above proceeding will be replaced by the following one of my invention,
obviating the above mentioned inconvenience by a more intimate combination of
the dyeing material with the paper.
For the production of the wished for hue of the paper some light-proof colour
soluble in water is made use of, chiefly cobalt-blue and the paper dyed with it.
This light-proof ground having been obtained the paper is covered with the
albumen layer and is then ready for being sensibilized with the solution of nitrate
of silver.
be
The above proceeding need not be limited to albuminized paper,
but may
adapted wherever a constant ground-colour is desireable for photographic-positives.
The innovation of the proceeding consists consequently in the separation of the
coloured solution, for the production of which a light-proof metallic colour or any
other as light-proof known suitable colour is made use of, from the albumen layer
proper and its previous appliance.
Dated. Hamburg. 19th day of November 1895.
I, GUSTAV KOPPMANN, Photographer, Hamburg, Billhörner Röhrendamm No. 54
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 a wellknown fact that the albuminized papers used for photographic
positives lose their beautiful rose or bluish tint after a short time. Hitherto the
proceeding consisted in mixing the corresponding colour solution with the albumen
5 covering the paper with this mixture. The colours used are the little light-proof
aniline colours mixing perfectly with the albumea.
The above proceeding will be replaced by the following one of my invention,
obviating the above mentioned inconvenience by a more intimate combination of
the dyeing material with the paper.

page_text: According to the proceeding of the applicant it is not any longer the solution
of albumen which is coloured, the paper to be used being on the contrary evenly
dyed with a layer of colour by an ordinary printing procedure. Hence the colour
is brought iuto direct contact with the superficies of the paper, wherein precisely
consists the innovation, and thus a possibility is given to employ a colour known as
indifferent to light, thus as for instance cobalt-blue.
It is only after submitting the paper to this printing process that it is covered
with albumen and afterwards treated in the known manner and then it is ready for
being sensitised with the solution of nitrate of silver.
The above proceeding need not be limited to albuminized paper but may be
adopted wherever a constant ground-colour is desirable for photographic positives.
The innovation of the proceeding consists consequently in the separation of the
coloured solution, for the production of which a light-proof metallic colour or any
other as light-proof known suitable colour is made use of, from the albumen layer
proper and its previous appliance.
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 :
Coloured positive paper wherein the coloured tint is produced by a light-proof
coloured raw-paper, as set forth.
D
TT
A21 .
"
GUSTAV KOPPMANN,
Applicant.
By Carl O. Lange,
Agent for Applicant.