IMPROVEMENTS IN PHOTOGRAPHY
Year: 1856

page_text: LETTERS PATENT to John Perry, of No. 14, Great Portland Street,
in the County of Middlesex, Artist, for the Invention of "IMPROVEMENTS
IN PHOTOGRAPHY."
Sealed the 20th February 1857, and dated the 26th August 1856.
PROVISIONAL SPECIFICATION left by the said John Perry at the Office.
of the Commissioners of Patents, with his Petition, on the 26th August
1856.
I, JOHN PERRY, of No. 14, Great Portland Street, in the County of
Middlesex, Artist, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN PHOTOGRAPHY," to be as follows:-
Having prepared the paper or other material used with chromic acid, or a
solution of one of the salts or combinations of chromium, and exposing the
same to light in the usual way, I firstly wash the same, and apply a solution
of protosulphate or one of the combinations of iron; secondly, I strengthen,
color, or darken the image with a solution of tannin, gallic acid, or other acid
of the like kind. I do not profess to confine myself exclusively to the use
of iron, but in some cases I propose to use silver, copper, tin, lead, zinc, or
other metal in conjunction with chromium, to produce change of tone or
modification of the image. In other instances I propose to employ the acetate

page_text: or other compound of iron without the chromium, in conjunction, however,
with the after use of tannin or gallic acid. I also propose, in certain stages
of this process, to use cyanogen and the alkalies with other articles used in
dyeing, in order to the production of colour, or to improve the general effect.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Perry in the Great Seal Patent Office on the
26th February 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
PERRY, of Number 14, Great Portland Street, in the County of Middlesex,
Artist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-sixth day of August, in the year of our Lord
One thousand eight hundred and fifty-six, in the twentieth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
John Perry, Her special licence that I, the said John Perry, my executors,
administrators, and assigns, or such others as I, the said John Perry, 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, use, exercise, and vend,
within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN PHOTOGRAPHY,"
upon the condition (amongst others) that I, the said John Perry, my executors
or administrators, 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 performed, 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 John Perry, do hereby declare the
nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:-
My Invention consists of certain processes, whereby photographic images or
pictures may be obtained, which will be absolutely permanent and insensible
to the action of solar light.

page_text: my
I may here state, that Invention relates to the preparation of what are
known as "positive" photographic pictures, such pictures being obtained or
printed by the operation of the solar light, from "negative" pictures previously
obtained on glass or other suitable material, in the manner well known to
persons conversant with photography.
In the first instance, I prepare the paper or other material to be used by
floating it on a saturated solution of chromate of ammonia or bichromate of
potash. The paper or other material having been then dried, may be used for
printing from the "negative" picture in the ordinary way, and the "positive"
impression or picture having been thus obtained, I thoroughly soak and wash
the same in pure water in order to dissolve and remove the chromium from
the high lights of the picture. The picture having been sufficiently washed,
I then dip the paper or other material in a solution of protosulphate of iron,
and having allowed it to remain a few minutes, I again subject the picture to
washing and soaking in pure water, and then pour on the same a small
quantity of gallic acid or pyrogallic acid, or tannin in solution, which imme-
diately combines with the iron already existing in the shadows of the picture,
and produces the depth of tone or colour required, or should the colour of the
picture be unsatisfactory, it can be modifled at pleasure by the use of a weak
solution of any of the alkalies or acids.
In the preparation of the paper or other material, I do not, however, con-
fine myself to the use of the chromate of ammonia or bichromate of potash,
but occasionally use other combinations of chromium, inasmuch as any of the
combinations of chromium or chromic acid with soda, silver, tin, lead, zinc,
bismuth, iron, cadmium, antimony, and nickel, may be employed for the like
purposes, and will produce the like results.
In some cases I use the chromate of iron in the preparation of the paper or
other material, in which cases, after the processes of printing and washing have
been effected, the picture is ready at once for the application of the gallic acid
or pyrogallic acid, or tannin, whereby the process is in some degree shortened
and simplified.
In some instances, and where great strength or depth of colour is desired,
I apply solutions of any of the soluble salts of silver, tin, lead, zinc, cadmium,
antimony, nickel, or bismuth, or any of the same combined with ammonia, to
the paper or other material previous to the application of the chromium.
I may here state, that I do not profess to confine myself exclusively to the
use of the proto-sulphate of iron, after the application of the chromium to
the paper or other material, in order to produce change of tone or modification

page_text: of colour, but occasionally use other compounds of iron, namely, the acetate,
nitrate, tartrate, citrate, oxalate, chloride, or phosphate, for such purposes; and
in some instances I employ, at the same stage of the process, any of the salts
of silver, copper, tin, lead, zinc, cadmium, antimony, nickle, or bismuth, for
the like purposes. In some cases also I employ the acetate, oxalate, tartrate,
or citrate of iron; or either of such salts combined with ammonia without the
chromium, but in conjunction with the subsequent use of tannin, or gallic
acid, or pyrogallic acid. In order also to produce colour and to improve the
general effect of the pictures, I sometimes use cyanogen and other analogous
articles used in dyeing, and which I apply to the paper or other material, in
the manner herein-before mentioned with reference to tannin, gallic acid, or
pyrogallic acid.
The processes herein-before described, are applicable to paper, linen, cotton,
metallic surfaces, and wood. In cases in which paper is employed, I sometimes
prepare the surface thereof with gelantine or size, in the manner already
understood, previous to the application of the chronium, as, by so doing, the
picture will be retained more on the surface, and a remarkable depth and
brilliancy of tone will be obtained.
The peculiar advantage of my Invention consists in the great durability or
permanency of the pictures obtained by means of the processes herein-before
detailed, and in the trifling cost at which such pictures can be produced.
Having now described and particularly ascertained the nature of my said
improvements, and the manner in which they are to be applied and used, I
would observe, in conclusion, that I do not confine or restrict myself to
the precise details or arrangements which I have described or referred to,
inasmuch as variations may be made therefrom, and chemical equivalents
employed or used instead, or in the place of the substances and compounds
herein-before mentioned, or some of them, without deviating or departing
from the principles or main features of the said Invention; and I wish it to
be distinctly understood that what I consider to be novel and original, and
therefore claim as the Invention secured to me by the herein-before in part
recited Letters Patent, is,-
Firstly, the use of chromic acid, or any of the combinations of chromium,
as a mordant or mordants in photographic printing, for the fixation of iron or
the other metallic bodies herein-before in that behalf mentioned, in conjunction
with tannin, gallic acid, or pyrogallic acid, or any compound or compounds
containing the same, or any mere chemical equivalents thereof.
And, secondly, the employment of the acetate or other salts of iron, herein-

page_text: before mentioned, with or without the use of chronium, in the production of
photographic images or pictures, when used in connection with the subsequent
application of tannin, gallic acid, or pyrogallic acid to the paper or other
material employed, as herein-before described, or any mere chemical equi-
valent or equivalents thereof.
In witness whereof, I, the said John Perry, have hereunto set my hand
and seal, this Twenty-sixth day of February, in the year of our Lord
One thousand eight hundred and fifty-seven.
Witness,
E. P. H. VAUGHAN,
59, Chancery Lane,
Agent for the Patentee.
JOHN PERRY. (L.S.)