We have already described the various remarkable photographic pictures
which may be taken by successive exposures with the same individual in
different positions against a perfectly black and non-actinic
background. This, however, is not easily obtained, and a French
photographer, M. Bracq, has invented an ingenious attachment to a
camera by which the same effects may be obtained with any background
and under the ordinary conditions of amateur photography. The
following description is from _La Nature_ translated in the _Popular
Science News_.
[Illustration: FIG. 70.]
The apparatus, Fig. 70, is attached to the back of the camera, and
consists of a frame suitable for holding the usual ground glass, or
plate holder. Directly in front of the plate holder is placed an
opaque screen perforated with a horizontal slit the width of the
photographic plate used. By means of a screw and a crank the screen
with its opening may be made to move up and down before the plate,
thus allowing all parts of it to be successively exposed. A pointer
connected with the screen shows the position of the slit at any time
when it is covered by the plate holder.
The operation of the apparatus is evident from the above description.
To take the picture illustrated in Fig. 71, for instance, the table
with the boy upon it is placed in the proper position and supported by
planks, another table, or in any convenient way. After properly
focusing it on the ground glass, the screen is screwed down till the
opening is at the bottom of the camera, and the plate holder being
placed in position, the slide is drawn and the handle turned till the
indicator shows that the opening has reached a point corresponding to
the image of the bottom of the table on the plate. The slide is then
replaced in the plate holder, the table and its support removed, and
the boy placed in the second position, and the exposure continued by
screwing up the screen until the entire plate has been impressed with
the double image, which, upon development, appears as shown in the
illustration.
[Illustration: FIG. 71.]
The perforated screen may also be made to move horizontally as well as
vertically across the plate, and by a combination of the two
directions the same individual may be taken four or more times in
different positions in the same photograph. Many amusing and
astonishing effects may be obtained by the simple means which will
readily suggest themselves to any practical photographer.