Improved Uranium Intensifiers and Reducers, as Applied to Photographic Negatives and Positives.
Year: 1896

page_text: Date of Application, 12th May, 1896
Complete Specification Left, 12th Feb., 1897-Accepted, 27th Mar., 1897
PROVISIONAL SPECIFICATION.
Improved Uranium Intensifiers and Reducers, as Applied to
Photographic Negatives and Positives.
We ALBERT HILL Manager Cresco-Fylma Co. Ld. 33 Thornhill Crescent
London, N. and THE CRESCO-FYLMA Co. LIMITED Photographic Dealers
33 Thornhill Crescent London N. do hereby declare the nature of this invention to
be as follows:-
This invention relates to improvements in the uses of the metal uranium, as
applied to the intensification and reduction of the amount of density on photographic
negatives, transparencies and bromide prints.
Uranium nitrate when used in combination with ferri-cyanide and acetic acid,
has the objection that where there is practically little or no silver reduced by the
developer; those parts stain, and render the increase of density and color so even,
or technically flat, to he of no great service.
Should this formula-(with modifications in the amount of chemicals to suit
special purposes)-be used the deposit of uranium is more regular and increase of
range of density or tone much greater, and the results more permenant.
The formula we prefer is as follows
Of either
Acetate of uranium - 120 grains.
Acetic acid or
Formic or citric acid}
oz.
Ferri-cyanide of potash 50 grains.
To this formula may be added for toning bromides, and transparencies special
colors, sulpho-cyanide of potassium or nitrate of strontium, from 5 to 70 grains.
Though we use acetic acid in the above formula, in the case of tabloids the other
ingredients would be ground together and mixed with some adhesive substance
(such as celluloid and amyl acetate) which though containing no water to start
chemical action, would be readily dissolved in acetic acid and water.
The negative or transparency to be treated is placed in the above solution and
the increase of density judged by viewing by transmitted light, and afterwards well
washed in water to which a small piece of carbonate of soda (1 dram in 20 oz.) has
been added.
If it is desired to reduce the amount of density, the film is first intensified, and
afterwards transferred to the ordinary hyposulphite of soda fixing bath, to which a
few drops (1 per cent.) of ammonia is added.
Dated his ath der of M. 1906
ALBERT HILL.
THE CRESCO-FYLMA CO., LIM,
H. ALBEY, Secretary.

page_text: COMI LEIE SPECIFICATION.
Improved Uranium Intensifiers and Reducers, as Applied to
Photographic Negatives and Positives.
We, ALBERT HILL Manager of The Cresco-Fylma Co. Ld. 33 Thornhill
Crescent, London, N. and THE CRESCO-FYLMA Co. LD. Photographic Dealers
33 Thornhill Crescent, N. 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 :-
This invention relates to improvements in the uses of the metal uranium as
applied to the intensification, and reduction of the amount of density on photographic
negatives, transparencies and bromide prints.
Uranium nitrate when used in combination with ferri-cyanide of potash and
acetic acid as is usual in photographic procedure, has the objection that, when
there is practically little or no silver reduced by the developer, those parts stain,
and render the increase of density and color so even or technically flat to be of no
great service.
Should this formula (with modifications in the amount of chemicals to suit
special purposes)-be used, the deposit of uranium is more regular, and increase
of range of density or tone much greater, and the results more permenant.
The formula we prefer is as follows-
Water
Acetate of uranium
Acetic acid -
-
6 oz.
120 grains.
}
oz.
Of either Formic or citric acid
Ferridcyanide of potash 50 grains.
To this formula may be added for toning bromides and transparencies special
colors, sulpho-cyanide of potassium or nitrate of strontium from 5 to 70 grains.
Though we may use acetic acid in the above formula, in the case of tabloids,
this ingredient would be omitted, the other ingredients ground together, and mixed
with some adhesive substance (such as celluloid and amyl acetate) which, though
containing no water to start chemical action, would be readily dissolved in acetic
acid and water.
The negative, positive or bromide print to be treated is immersed in the above
solution, and the increase of density judged by viewing by transmitted light, and
afterwards well washed in water to which a small piece of carbonate of soda (1 dram
in 20 oz.) has been added.
If it is desired to reduce the amount of density, the film is first intensified, and
afterwards transferred to the ordinary hyposulphite of soda fixing bath, to which a
few drops (1 per cent.)-of ammonia is added.
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 :-
I. The use of acetate of uranium in combination with a suitable acid and
ferricyanide of potash for intensifying and reducing photographic negatives and
positives substantially as described.
II. The use of acetate of uranium, in combination with a suitable acid and
ferricyanide of potash, to which is added nitrate of strontium or sulphocyanide of
notash substantially as described.

page_text: III. Tabloids containing amyl acetate celluloid, acetate of uranium, ferricyanide
of potash and citric acid, substantially as described.
Dated this 11th February 1897.
ALBERT HILL
and
THE CRESCO-FYLMA CO., LD.,
H. ALBEY, Secretary.