IMPROVEMENTS IN THE FORMATION OF GELATINO-BROMIDE FILM PAPER FOR PHOTOGRAPHIC NEGATIVES
Year: 1883

page_text: LETTERS PATENT to Raphael Hunter Brandon of N° 1 Rue Laffitte, Paris
in the Republic of France Engineer and Patent Agent for an Invention of
"IMPROVEMENTS IN THE FORMATION OF GELATINO-BROMIDE FILM PAPER FOR
PHOTOGRAPHIC NEGATIVES A communication to him by Alphonse Charles
Auguste Thiébaut Photographer of N° 1 Rue Laffitte Paris France
COMPLETE SPECIFICATION filed by the said Raphael Hunter Brandon at
the Office of the Commissioners of Patents on the 30th March 1883.
RAPHAEL HUNTER BRANDON of N° 1 rue Laffitte Paris, in the Republic of
France engineer and patent agent. IMPROVEMENTS IN THE FORMATION
GELATINO-BROMIDE FILM PAPER FOR PHOTOGRAPHIC NEGATIVES, A communication
from Alphonse Charles Auguste Thiébaut photographer of N° 1 Rue Laffitte Paris
France
OF
This invention consists in the preparation of a gelatinised bromide of silver film
paper from which the pellicle or film after the photographic negative has been
produced by exposure & developement in the usual manner is detached or peeled
off in a dry state by hand without the assistance of any dissolving or other
agent.
Since the discovery and use of rapid glasses prepared with gelatine and bromide
of silver, constant efforts and trials have been made to replace the glass universally
used, by a light support, not brittle as fine and as transparent as glass and at the
same time easily handled for the purpose of obtaining photographic negatives.
The paper which I have invented for this purpose answers all the requirements.
of the art and has the following advantages;
First The sensitive coating is regular and its thickness is uniform throughout
the entire surface of each sheet.
Second It can be exposed for a luminous impression in any kind of slide as
usually constructed.
Third It can be developped and fixed as easily as a negative on glass.
Fourth The negative obtained dries quite flat on blotting-paper.
Fifth The film which constitutes the negative can be detached or peeled from

page_text: .
its support or backing easily and readily by the hand, without the assistance of
any dissolving or other agent. Thus this invention does away with all sensitive
preparations on glass, which latter is both a brittle and relatively heavy material,
thus diminishing the bulk and weight of amateur's and scientific photographers
fine and as
luggage when travelling; it produces photographic negatives as
transparent as those on glass, in so much that the film does not contain any grain
and lastly it admits of printing from either face of the film, as regards the pro-
duction of positives on paper or other material as well as plates for Phototypy and
Photo-engraving which latter processes require a negative to be reversed.
For the manufacture of my sensitised film paper.
Firstly. A gelatinised sheet of paper is properly damped with cold water and
when evenly saturated it is placed on a glass to which it is attached by means of
bands of paper pasted partially on the glass and partially on the edges of the said
sheet, in this state it is allowed to dry whereby it is stretched quite flat.
Secondly I coat the dry sheet with a solution of ordinary collodion containing
from one to two per cent cubic measure of azotic cotton (1) per cent gives very
good results) and from 1 to 2 per cent of castor oil (2 per cent gives very good
results), this coating is allowed to dry and,
Thirdly The glass with the prepared paper upwards is levelled and then it is
coated, in a room from which all rays but red rays of light are excluded with a
tepid emulsion of bromide of silver to the extent of about one millimeter thick and
after leaving it in this position until the gelatine has set say about 5 minutes,
with the film paper still attached, it is placed upright in a drying room, where it
should remain about 12 hours exposed to a temperatue of from 62 to 66 degrees
Fahrenheit and
Fourthly The film-paper is detached from the glass ready for exposure
development and fixing in the usual manner, for the purpose of developing oxalate
of iron or pyrogalic acid answer equally well, for the purpose of fixing. I have
found that a mixture by weight, water 1000, hyposulphite of soda 150 and
powdered alum 60 produces excellent results; after being allowed to dry.
Fifthly The film is peeled off the paper by hand and can be immediately used
for producing negatives recto or verso as above mentioned.
I claim as my Invention:
.
Firstly The preparation or formation of gelatino-bromide film paper for
photographic negatives in the manner and for the purposes above described and .
Secondly The use for this purpose of castor oil or any other analogous oil, more
especially with the view of peeling off the film from the paper backing as above
described.
In witness whereof I the said Raphael Hunter Brandon have hereunto set
my hand and seal this 29th day of March One thousand eight hundred and
:
eighty three
Witnesses:
H. MEA
P. SCHOLTUS
3.
R. H. BRANDON (L.S.)::