IMPROVEMENTS IN PHOTOGRAPHY
Year: 1870

page_text: PROVISIONAL SPECIFICATION. left by Thomas George Hemery at the
Office. of the Commissioners of Patents, with his Petition, on the
12th January 1870.
I, THOMAS GEORGE HEMERY, of 8%, Bruton Street, Berkeley Square,-
in the County of Middlesex, Photographer, do hereby declare the nature
of the said Invention for "IMPROVEMENTS IN PHOTOGRAPHY," to be as
follows:-
-
The Invention relates to the production of a single negative from the
combination of several negatives or of a single negative embracing the-
effects of the combination of several negatives.
I
.
.
The object of the Invention may be obtained in various ways...
Supposing the picture intended to be produced be the representation.
together of two sitters, one partly over or covering the other, similar. to.
the combination portraits in profile on medallions and coins..
In the following description I mean by the first or principal figure
the front or eclipsing body, and by the second figure I mean the one
partially eclipsed.
;

page_text: By one method (No. 1). First, the principal figure is photographed
and developed in the usual way, the background being by preference
black, or such as will give a transparent background to the negative
after developement. I now generally dry and varnish the negative and
cover the figure neatly with an opaque varnish or substance capable of
subsequent removal. The remainder of the plate is to be perfectly
transparent and the film carefully removed if necessary, I now coat
the back of the plate and excite in the usual manner. Then focus the
second figure through the ground glass, turning its ground side outward
for this purpose. The plate is then put in the slide with the opaque
image to the lens, and the second figure is impressed through the glass,
which having the opaque image on its front surface is left with an exact
counterpart of the first figure perfectly transparent after developement.
I now remove the opaque substance from the first figure with a brush,
sponge, or other suitable means, and take a transparency of the double
negative, which will combine perfectly together. I now proceed as
usual for the final negative, which may be enlarged or reduced at
pleasure. If it is not thought advisable to immerse a plate in the
nitrate or exciting bath containing on one surface an image covered
with varnish or other material that might be thought to contaminate it
then a second method may be followed.
(No. 2.) Take two impressions of the first figure consecutively without
any change of position on the part of cither sitter or camera. Now
while the second plate is preparing one of the first pair may be rendered
opaque and the film removed from it if the background is not suffi-
ciently transparent. It is now placed in the dark slide immediately in
front the wires on which the plate rests, the dark slide may want
adjusting for this purpose. The second plate is placed in this instance,
not as in method No. 1; but as usual the prepared or excited. side
towards the lens and the second figure impressed, which, as before,
having an opaque image in front is left with a perfect aperture into
which the other or non-opaque figure will exactly fit or register when
the two plates are subsequently brought into contact. The transparency
and subsequent negative may then be taken as in method No. 1.
Another method (No. 3) is one which perhaps offers the least trouble
to sitters, as all the manipulative portion is done in their absence. The
first or principal figure is taken twice consecutively on one plate without
change of position either of sitter or camera, but with two backgrounds,

page_text: one by preference pure black, or such as will give a transparent back-
ground to the plate, and the other white or such as will give an opaque
background to the plate. The second figure is photographed on another
plate with an ordinary background, but a dark background I find most
suitable for the purpose. Now superimpose the negative of the first
sitter with the black or transparent background, having first rendered
the figure opaque and removed the background film if not sufficiently
transparent, and take a transparency of the combination. Now slide the
two negatives that are in front of the lens, or slide the camera or lens
for the same purpose till the second figure of the first or principal sitter
with the white background occupies the same position as the combined
negatives previously did. It is desirable that the background of this
figure be sufficiently opaque to keep the glass clean and transparent in
the transparency now to be taken, and if not so it may be covered with
paper, color, or other suitable material. The figure being now in
position slide the plate in the camera and expose for the second
transparency without refocussing. On developing the plate one half
has a portion of the second with a transparent receptacle into which
the transparency of the second figure of the first or principal sitter
on the other half of the plate fits; I now cut the plate in two and
combine the transparencies, and they will yield a perfect negative equal'
in every respect to the merits of the original separate negatives. The
transparencies may be taken on separate plates if desired.
The combining several negatives into one according to my Invention
is applicable to two or more figures, or two or more negatives being parts
of a picture or subject, as well as two portraits for the production of one
ultimate and final negative. I do not confine myself to the precise
details herein given.
If the negatives are greater in number than two, then the same
method is. followed as in No. 2, continuing the masking for each part
of the picture, and if more transparencies than one are necessary to be
taken, then the recombination of these transparencies will furnish the
complete or final negative.