AŃ Improved SubSTANCE TO BE USED INSTEAD OF COLLODION AND OTHER EMULSIONS FOR PHOTOGRAPHIC PURPOSES
Year: 1873

page_text: LETTERS PATENT to Richard Kennett, of Maddox Street, in the
County of Middlesex, for the Invention of "AŃ Improved SubSTANCE
TO BE USED INSTEAD OF COLLODION AND OTHER EMULSIONS FOR PHOTOGRAPHIC
PURPOSES."
Sealed the 10th March 1874, and dated the 20th November 1873.
PROVISIONAL SPECIFICATION left by the said Richard Kennett at
the Office of the Commissioners of Patents, with his Petition, on
the 20th November 1873.
I, RICHARD KENNETT, of Maddox Street, in the County of Middlesex,
do hereby declare the nature of the said Invention for "AN IMPROVED
SUBSTANCE TO BE USED INSTEAD OF COLLODION AND OTHER EMULSIONS FOR PHOTO-
GRAPHIC PURPOSES," to be as follows:-
.
The object of my said Invention is the production of a new substance
or compound to form an emulsion for photographic purposes, and which
may be prepared and sold in a dry or solid condition, and will keep
perfectly good for any length of time.

page_text: My said improved substance or compound consists essentially of
gelatine or gelatinous matter in combination with bromide of potas-
sium, bromide of cadmium, bromide of ammonium, or the chloride of
either of these substances and nitrate of silver.
In making the said compound I prefer to employ the following sub-
stances and process, that is to say, I place in a dish or pan of porcelain
or other suitable material about one pound of the substance known as
Nelson's gelatine, or other suitable gelatinous matter, to which I add
about one hundred and fifty ounces of distilled water. This mixture of
gelatine and water is allowed to stand for about three hours to soften
the gelatine, and is then heated by a hot water bath or otherwise until
the gelatine is thoroughly dissolved. I then add to it about eight and
a quarter ounces of the bromide of potassium dissolved in water,
and which must be thoroughly incorporated with the gelatine by
stirring. I then add to the compound by stirring the same, eleven and
one half ounces of nitrateof silver dissolved in water; the whole of the
above operations must be effected while the gelatine is hot. At this
stage of the process the said compound or emulsion will contain free
bromide and nitrate of potassium, the latter of which I eliminaté as
follows: I pour the emulsion into glass or porcelain dishes, to the depth
of about a quarter of an inch and let it stand long enough to become
cold, I then wash it with distilled water.
Instead of the bromide of potassium I may use bromide of cadmium.
or of ammonium, or the chlorides of potassium, cadmium, or ammonium,
and I sometimes add to the compound made with either of these salts a
small quantity of the iodide of the same salt.
The quantity of gelatine used in the said compound may be varied to
any desired extent, but the salts must always be in such proportion to
each other that there will be a slight excess of the bromide or chloride
beyond its equivalent of combination with the nitrate of silver. The
said compound is then ready for immediate use but will not keep good
beyond a short time. Therefore I dry or desiccate the same to render it
capable of preservation for any length of time, and thereby fully accom-
plish the object of my Invention. For this purpose I place the com-
pound or emulsion in flat dishes which are heated by hot water boilers or
I otherwise heat the said dishes till by evaporation the said compound is
reduced to the consistency of a thick paste. Then the compound is allowed

page_text: to stand until it becomes cold; it is then removed by stripping it from
the dishes and is placed in suitable frames in a drying closet in which
a circulation of dry air, either warm or cold is maintained, whereby the
drying or desiccation is completed. Or I may employ other methods
of effecting the desiccation of the compound instead of that above
described. When dry the said compound is cut into portions of con-
venient size and is then ready for the market. The whole of the above
described process must be conducted in a very weak or non-actinic
light. When used the compound must be dissolved in water. It is
to be used in connection with the alkaline developer commonly employed
for dry plates.
If desired the bromized or chlorodized gelatine may be dried without
the nitrate of silver, and sold in that condition; it will then require to
be sensitized when used.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Richard Kennett in the Great Seal Patent Office
on the 20th May 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, RICHARD
KENNETT, of Maddox Street, in the County of Middlesex, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twentieth day of November, in the
year of our Lord One thousand eight hundred and seventy-three, in
the thirty-seventh year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said Richard Kennett, Her
special licence, that I, the said Richard Kennett, my executors,
administrators, and assigns, or such others as I, the said Richard
Kennett, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make,
usc, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention
for "AN IMPROVED SUBSTANCE TO BE USED INSTEAD OF COLLODION AND OTHER
EMULSIONS FOR PHOTOGRAPHIC PURPOSES," upon the condition (amongst

page_text: others) that I, the said Richard Kennett, my executors or adminis-
trators, by an instrument in writing under my, or their, or one of their
hands and seals, should particularly describe and ascertain the nature
of the said Invention, and in what manner the same was to be per-
formed, and cause the same to be filed in the Great Seal Patent Office
within six calendar months next and immediately after the date of the
said Letters Patent.
NOW KNOW YE, that I, the said Richard Kennett, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement :-
The object of my said Invention is the production of a new substance
or compound to form an emulsion for photographic purposes, and which
when prepared and sold in a dry or solid condition will keep in this con-
dition perfectly good for any length of time.
My said improved substance or compound consists essentially of
gelatine or gelatinous matter in combination with nitrate of silver and
with bromide of potassium, bromide of cadmium, bromide of ammonium,
or with the chloride or the iodide of either of these salts in combi-
nation with either of the bromides above specified.
In making the said compound I prefer to employ the following
materials and process, that is to say, I place in a dish or pan of porcelain
or other suitable material about one pound of the substance known as
Nelson's gelatine or other suitable gelatinous matter, to which I add
about one hundred ounces of distilled water. This mixture of gelatine
and water is allowed to stand for about three hours to soften the gelatine,
and is then heated by a hot water bath or otherwise until the gelatine
is thoroughly dissolved, I then add to the mixture or compound about
eight and a quarter ounces of the bromide of potassium dissolved in
water, and which must be thoroughly incorporated with the gelatine by
stirring. I then incorporate with the said compound while stirring
the same, eleven and one-half ounces of nitrate of silver dissolved in
water. The whole of the above operations must be effected while the
gelatine is hot. At this stage of the process the said compound or
emulsion will contain free bromide of potassium, and nitrate of potassa,
which must be eliminated and which I eliminate as follows:-I pour
the emulsion into-glass or porcelain dishes to the depth of about a

page_text: quarter of an inch and let it stand long enough to become cold. I then
remove it from the dishes and cut it in small strips and wash it with
many changes of water, or in running water until the free salts are all
dissolved out. I then dry or desiccate the substance or compound to
render it capable of preservation for any length of time, and therefore
fully accomplish the object of my Invention. For this purpose I place
the compound or emulsion in flat dishes which are placed upon hot
water boilers, or otherwise heated until the said compound is reduced by
evaporation to the consistency of a thick paste. Then the said com-
pound or substance is allowed to stand until it becomes cold; it is then
removed by stripping it from the said dishes and is placed in suitable
frames in a drying closet in which a circulation of dry air, either warm
or cold, is maintained, whereby the drying or desiccation is completed.
It will be seen from the above description that the proper drying or
desiccation of the compound is very essential to the success of my
Invention, but I wish it understood. that I may employ any other
suitable and convenient method of effecting the drying or desiccation of
the compound instead of that above described. For instance I may
take the said substance or compound after washing the same to dissolve
out the free salts and place it at once in the said drying closet, or expose
it to an air blast and thereby effect the drying or desiccation entirely
without the application of heat. When dry the said compound is cut
into portions of convenient size, and in this condition will be ready for
immediate use, or will keep perfectly good for a very long time. It
may be conveniently made up into small packets for transmission by
post to artists or amateurs in any part of the world. It is unaffected
by changes of temperature or climate, and will render the plates to
which it is applied highly sensitive, so that good pictures of animals and
other moving objects may be easily obtained.
The whole of the above described process for the manufacture of my
new compound or substance must be conducted in a very weak non-
actinic light. The quantity of gelatine used in the said compound may
be varied to any desired extent, but the salts must always be in such
proportion that there will be a slight excess of the bromide or chloride
beyond its equivalent of combination with the nitrate of silver. Before
its application to the plates the said compound or substance must be
dissolved in warm water, and it should be used in connection with the
alkaline developer for dry plates.

page_text: Having thus fully described my said Invention and the manner of
performing the same, I wish it understood that I claim, a substance or
compound for forming photographic emulsions which, when prepared in
a dry or solid condition as herein set forth, will remain perfectly good
and fit for use for any required time.
In witness whereof, I, the said Richard Kennett, have hereunto set
my hand and seal, this Nineteenth day of May, in the year of our
Lord, One thousand eight hundred and seventy-four.
Witness,
WM. ROBT. LAKE,
8, Southampton Buildings,
London.
R. KENI
(L.S.)