In- PROVEMENTS IN PHOTOGRAPHIC PICTURES, AND IN APPARATUS FOR PRODUCING THEM
Year: 1867

page_text: PROVISIONAL SPECIFICATION left by Ernest Edwards at the Office of
the Commissioners of Patents, with his Petition, on the 23rd March
1867.
I, ERNEST EDWARDS, of 20, Baker Street, Portman Square, in the County
of Middlesex, do hereby declare the nature of the said Invention for "In-
PROVEMENTS IN PHOTOGRAPHIC PICTURES, AND IN APPARATUS FOR PRODUCING THEM,'
to be as follows:-
This Invention consists in taking in the ordinary way a small photographic
negative by means of a lens of very short focus and large aperture, giving
very fine microscopic definition with freedom from spherical aberration; this
lens is fitted to a suitable camera so arranged that one or more different
photographic pictures can be produced in it successively upon the same
sensitive plate; these pictures are obtained by exposing different parts of the
plate to the action of the light from the lens by means of an instantaneous
shutter placed in front of the lens or behind it (which I prefer in photo-
graphing landscapes). The glass plate upon which the negative pictures are
produced must be perfectly free from flaws. The collodion must be such as
will give a film without "structure," and the light used in taking portraits
should be modified by passing through blinds of tracing cloth or other suitable
material. In sensitizing the plate I use a silver bath of full strength and
neutral or slightly acid. After taking the small negative pictures in the camera
I develop them with a solution of sulphate of iron, to which is added loaf
sugar and pure alcohol in variable proportions, but no acid whatever; and I

page_text: fix the pictures with a solution of hyposulphite of soda, and varnish them
with carefully filtered varnish. In order to print copies (enlarged to any
size) from the negatives thus obtained I attach the lens and camera by which
they have been produced, or precisely similar ones, to the front of another
camera prepared to receive them, which may be of the ordinary form or made
with a back of the construction herein-after described. The first camera is
attached to the second one, so that the light, either natural or artificial, passes
through one of the small negatives already described, and is then transmitted
through the lens on to a moveable ground glass fitted into the back of the
second camera, upon which it is focussed of any size required by regulating
the distances between the negative and the lens and between the lens and the
ground glass; I then take a mixture of collodion and a solution of white wax
in ether, and I pour some of this mixture upon a plate either of opal glass or
ordinary glass, and having carefully rubbed off this mixture I coat the plate
with a suitable collodion sensitized in a bath made very acid with nitric acid;
I then place this sensitized plate in a suitable dark frame, which I substitute
for the ground glass in the second camera described above, and I expose the
sensitized plate to the light which has first passed through the small negative
and lens. After exposure I develope the picture thus obtained with a very
weak solution of a developing agent, to which a large quantity of acetic acid
has been added, and I fix the picture with a solution of cyanide of potassium,
and then treat it with bichloride of mercury, to which salts of gold or uranium
or other substances to produce different tones in the picture may be added;
the picture is finally washed with a weak solution of hyposulphite of soda, and
afterwards dried; when dry the plate with the adhering picture is immersed
in water; at the same time with a piece of paper, either plain or enamelled,
prepared or coated with gelatine, and the surfaces of both having been first
freed from air bubbles, are brought into close contact, and are then withdrawn
together from the water; they are then put under moderate pressure, and
after a short time the paper is separated from the plate of glass and brings
with it the collodion picture, which will remain firmly attached to it; the
picture is then dried and may be mounted in any convenient way, or it may
when it is dry be coated with varnish or gelatine for its better preservation,
or when it is intended to be colored with a solution of gum arabic. The
instantaneous shutter above described for taking pictures with a small lens
consists of a plate turning upon a centre by means of a handle, and having an
aperture in it which can be brought opposite the lens by moving the handle.
when the handle is moved back the aperture is removed from the lens, from
which the light is then excluded. And in order to produce vignette prints, or

page_text: prints with white margins of different shapes, I use plates or masks having
apertures of suitable shapes which I drop into the aperture ordinarily occupied
by the shutter of the dark slide. And I use a frame to contain the sensitized
plates on which the enlarged pictures are to be taken, but which can be used
in any ordinary camera with two shutters or slides arranged so that they can
be opened or separated from one another to any distance required, and by this
means several pictures of the same or different sizes may be taken upon the
same plate. By means of this Invention I take small, sharp, and quick
negatives, from which I can rapidly print pictures of any size, and I am
enabled to take more perfect pictures with a less amount of light, great
economy of time is effected, and the apparatus required is much simpler than
usual. The pictures produced from life or from nature are much more per-
manent, and can be obtained of any size required from the same negative by
one operation without any sacrifice of pictorial qualities. Portraits from life
can be taken and finished proofs obtained in a few minutes exceeding in
roundness, softness, and modelling those obtained by any other process. By
this Invention too a very great rapidity in the production of prints is obtained,
and the negatives used can in no way be damaged in printing from them.