[Illustration: FIG. 91.--A DOUBLE. BY H. G. READING.]
Some very amusing pictures can be made by double exposure. For
instance, Fig. 91 represents a man playing cards with himself. A
method of making these is thus described by W. J. Hickmott in "The
American Annual of Photography for 1894":
[Illustration: By Leonard M. Davis. FIG. 90.--FAREWELL RECEPTION TO
THE PRINCE OF WALES.]
[Illustration: FIG. 91.]
[Illustration: FIG. 92.]
[Illustration: FIG. 93.]
Fit an open square box into the back of the camera, having it fully as
large as, or a little larger than, the negatives you wish to make. My
attachment is made for 8 x 10 plates and under, and fits into the back
of a 10 x 12 camera. In shape it is like Fig. 91, and I will designate
it as A. The box is about 3 inches deep. When put into the camera it
appears as in Fig. 92. Now have a plain strip of wood just one-half
the size of the opening in A like B, Fig. 93. Have B fit very nicely
in A, at the opening toward the lens, and so that it can be moved
freely from one side to the other. It is very convenient to have a
rabbet on the top and bottom of A so that B can be moved from side to
side and maintained in any position.
[Illustration: FIG. 94.]
To make a "Double," attach A to the camera as shown, put B into its
place in the opening in A, say on the right-hand side as you stand
back of your camera, thus covering up the right-hand side of the plate
when exposure is made. Pose your subject on the left hand side, which
will give you an image on the right-hand side of your ground glass and
plate, draw the slide and expose, immediately returning the slide.
This finishes one half of the operation. Shift B over to the left-hand
side of A, which will cover up that portion of the plate just exposed,
pose your subject again, but on the left-hand side, which will give
you the image on the right-hand side of the ground glass and plate,
draw the slide and expose out for the exact length of time as at
first. On development, if the exposure on both sides has been correct,
and of equal length, a perfect negative will be the result.
The camera must on no account be moved between the exposures, nor the
focus changed. After making the first exposure the correct focus for
the second is obtained by moving the subject backward or forward until
an exact focus is secured, and not by moving the camera or ground
glass. The whole apparatus should be painted a dead black.
When the attachment is in place it will be noted on the ground glass
that while the strip B is just one-half the size of the opening in A,
it does not cut off just one-half of the ground glass, a line drawn
through the center of which shows that a space in the center of the
plate about one-half an inch in width receives a double exposure, but
this is not apparent in the finished negative. The figure should be
posed as near the center of the plate as possible in each instance.
This apparatus, as described, is only available for making two
figures. By making B narrower, or one-third of the width of the
opening in A, three figures may be made, using each time a separate
piece to cover up that portion of the plate exposed, and by changing
the form of B to that shown in Fig. 95, four positions can be secured.
[Illustration: FIG. 95.]
Val Starnes describes[8] another and still simpler method. He says:
Take a light card, mount and carefully cut from it a disc that will
fit snugly inside the rim of the hood of your lens, resting against
the circular interior shoulder (Fig. 96). Cut from this, in a
straight, true line, a small segment (Fig. 97). The exact amount to
cut off you can determine by slowly thrusting with one hand a card
with a straight edge across the lens hood, looking the while at the
ground glass; when the shadow has crept _almost_ to the center of the
focusing screen, hold the card firmly in place and notice how much of
the circle of the hood is covered by it: cut from your disc a segment
corresponding to the amount _left uncovered_. Don't let the shadow
creep _quite_ to the center of the ground glass, for you might go the
least bit beyond, and an unexposed strip would result. Now paint your
disc a dull black; loosen the hood of your lens on its threads, so
that it will revolve easily and freely, and you are ready for
business.
[8] "American Annual for 1895."
[Illustration: FIG. 96.]
[Illustration: FIG. 97.]
Get your focus and then place disc in hood of lens, straight edge
perpendicular (Fig. 98). Cover lens with cap or shutter; insert
plate-holder and draw slide; pose your figure _directly in front of
uncovered portion of lens_; expose. Next, without touching disc,
slide, or anything but the hood, gently revolve the hood on its
threads one-half turn (Fig. 99), and pose your figure on opposite
side; expose. The trick's accomplished.
[Illustration: FIG. 98.]
[Illustration: FIG. 99.]
Another arrangement devised by Mr. Frank A. Gilmore, of Auburn, R. I.,
is shown in Fig. 100.
A black-lined box is fitted to the front of a camera. The front of the
box is closed by two doors. On opening one door a picture may be taken
on one side of the plate; on closing this door and opening the other,
the other half of the plate is ready for exposure.
[Illustration: FIG. 100.--CAMERA FITTED WITH ARRANGEMENT FOR DUPLEX
PHOTOGRAPHY.]
The subject poses in one position and is photographed with one door
open, care being taken to bring the figure within the proper area of
the negative. The finder enables this detail to be attended to. Then
the door is closed, the other is opened and the second exposure for
the other half of the plate is made with the subject in the other
position. It is not necessary to touch the plate-holder between the
exposures. The cover is withdrawn, the one door is opened and the
shutter is sprung. The doors are then changed and the shutter is
sprung a second time. Time exposures are rather risky, as involving
danger of shaking. A picture made by Mr. Gilmore will be found on the
next page.
[Illustration: By F. A. Gilmore. From _Scientific American_. FIG.
101.--SPARRING WITH HIMSELF]