Improvements in Photographic Paper Adapted for Printing Out and other Purposes
Year: 1899

page_text: Date of Application, 16th June, 1899
Complete Specification Left, 5th Mar., 1900-Accepted, 7th Apr., 1900
PROVISIONAL SPECIFICATION.
Improvements in Photographic Paper Adapted for Printing Out and
other Purposes:
A communication from abroad by ARTHUR SCHWARZ, of Steglitz, near Berlin,
.in the German Empire, Manager of Works.
We, THE ROTARY PHOTOGRAPHIC COMPANY, LIMITED, of 23, Austin Friars, in
the City of London, do hereby delare the nature of this invention to be as
follows:-
This invention relates to certain improvements in photographic paper adapted
for printing out and other purposes such as for the production of negatives,
transparent positives and other purposes.
It consists in the production of a sensitive paper from a raw paper which is
as far as possible transparent and grainless such paper being treated on both
sides with different sensitive solutions (such as those of bromide, of silver or
other suitable solutions) so that it may be used either for producing positives
or transparent positives or directly to produce negatives. The two surfaces
being of different sensitiveness enables the user to employ whichever side is
most suitable according to the character of the plate or film he is printing from.
As usually prepared papers for use in producing positives have one side coated
or treated with a more or less solid dressing of baryta or lime for the purpose
of supporting the sensitive layer which is to be afterwards applied. If this sup-
porting medium be not used the chemicals will penetrate the grain or fibre
of the paper with the result of producing an ineffective and indistinct picture.
According to the present invention this supporting medium can be entirely
dispensed with for the reason that once the gelatine or albumen solution or
the like serving as the support or vehicle for the sensitive salts has become
solidified, on one side the emulsion subsequently applied to the other side will
be prevented by the first coating from penetrating the thin paper.
There is no difficulty in obtaining distinct copies in the printing out process
with the present paper for the reason that on exposing the front surface to the
light the transparency of the paper enables the light to practically simultaneously
reach the emulsion on the back surface.
The finished picture on one side of the paper is therefore enhanced by the
finished image on the other side though the latter is less intense than the
former. A further result of this double treatment of the paper is that it allows
of a reduction in the period of exposure a fact which in certain operations
as for instance, for enlargements. is of considerable importance.
By using two emulsions of a different character the use of separate papers
for negatives of different characters or density may be avoided.
For instance one side of the paper may be prepared with a soft, and highly
sensitive emulsion and the other with a highly contrasting and less sensitive
emulsion, so that a substitute for two papers varying in sensitiveness is provided.

page_text: Owing to the different densities of the shadows and depths of the images on
both sides of the paper, it will when looked through present a very complete
representation of the image upon it. -
In the case of such transparent positives the paper so treated acts as a
deadened plate when seen through, so that the auxiliary devices which have
heretofore been employed such as ground glass milk or opal glass or the like
to act as a base may be dispensed with.
Dated this 16th day of June 1800
PHILIP M. JUSTICE,
55 and 56, Chancery Lane, London, W.C., Agent for the Applicants.
Improvements in Photographic Paper Adapted for Printing Out and
other Purposes.
We, THE ROTARY PHOTOGRAPHIC COMPANY, LIMITED, of 23, Austin Friars, in
the City of London, do hereby declare the nature of this invention (a communi-
cation from abroad by Arthur Schwarz, of Steglitz, near Berlin, in the German
Empire, Manager of Works) and in what manner the same is to be performed
to be particularly described and ascertained in and by the following statement: —
This invention relates to certain improvements in photographic paper adapted
for printing out and other purposes such as for the production of negatives, trans-
parent positives and other purposes.
It consists in the production of a sensitive paper from a raw paper which is as
far as possible transparent and grainless such paper being treated on both sides
with different sensitive solutions (such as those of bromide of silver or other
suitable. solutions) so that it may be used either for producing positives or
transparent positives or directly to produce negatives. The two surfaces being
of different sensitiveness enables the user to employ whichever side is most
suitable according to the character of the plate or film he is printing from.
As usually prepared, papers for use in producing positives have one side
coated or treated with a more or less solid dressing of baryta or lime for the
purpose of supporting the sensitive layer which is to be afterwards applied. If
this supporting medium be not used the chemicals will penetrate the grain or
fibre of the paper with the result of producing an ineffective and indistinct
picture.
According to the present invention this supporting medium can be entirely
dispensed with for the reason that once the gelatine or albumen solution or
the like serving as the support or vehicle for the sensitive salts has become
solidified, on one side the emulsion subsequently applied to the other side will
be prevented by the first coating from penetrating the thin paper.
There is no difficulty in obtaining distinct copies in the printing out process
with the present paper for the reason that on exposing the front surface to the
light the transparency of the paper enables the light to practically simultaneously
reach the emulsion on the back surface.
The finished picture on one side of the paper is therefore enhanced by the
finished image on the other side though the latter is less intense than the former.
A further. result of this double treatment of the paper is that it allows of a
reduction in the period of exposure a fact which in certain operations, as for
instance, for enlargements, is of considerable importance.
By using two emulsions of a different character the use of separate papers for
negatives of different character or density may be avoided.

page_text: .
For instance one side of the paper may be prepared with a soft and highly
sensitive emulsion and the other with a highly contrasting and less sensitive
emulsion, so that a substitute for two papers varying in sensitiveness is provided.
Owing to the different densities of the shadows and depths of the images on
both sides of the paper, it will when looked through present a very complete
representation of the image upon it.
In the case of such transparent positives the paper so treated acts as a
deadened plate when seen through, so that the auxiliary devices which have
heretofore been employed such as ground glass milk or opal glass or the like
to act as a base may be dispensed with.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed as communicated
to us from abroad we declare that what we claim is: -
1. A photographic paper having a surface on either side of different degrees
of sensitiveness substantially as described.
2. A transparent photographic paper prepared as described having a surface
on either side of different degrees of sensitiveness substantially as described.
Dated the 5th day of March 1900.
PHILIP M. JUSTICE,
55 & 56, Chancery Lane, W.C., London,
Chartered Patent Agent for the Applicants.