the curved paper or cardboard in such fashion that the
light will strike the paper or board and be reflected by the curved
surface to the object.

The lamps should be close enough to the paper or board to give the
maximum light. Care should be exercised, however, not to place them
too close, because of the fire hazard.

Any arrangement of lamps and reflectors giving a similar effect as the
above should prove suitable.

Fingers or skin which have a mottled, reddish-brown color because of
decomposition, exposure to severe heat, or diffusion with blood
present a problem of lack of contrast between ridges and depressions
for photographic purposes. This lack of contrast can be overcome to a
large extent by the use of a yellow or light red filter. Sometimes, in
those cases where the discoloration is due to the diffusion of blood
throughout the tissues, the blood can be washed out by saturating and
rinsing the specimen in a 10- to 20-percent solution of citric acid.
If, of course, the blood is not removed satisfactorily, the
photographing should be done with the filter.

[Illustration: 401]

As previously stated, the fingerprint camera can be readily adapted to
the use of photographing fingers or skin specimens for ridge detail.
Sometimes it is possible to photograph the skin or finger in the same
manner as one does a latent print. There will be instances, however,
in which the standard use of the fingerprint camera will not be
possible or effective, such as for side light, reflected light, and
sometimes transmitted light, or instances in which it is not possible
to get the finger or skin flush with the opening of the camera. In
these instances the lights of the camera are not used, so the
batteries should be removed and gooseneck lamps or other suitable
lighting equipment and ground glass utilized when the finger or skin
is prepared for photographing (fig. 402).

The camera is opened either at the point where the lights are housed
or at the lens point, whichever is most effective. Then, opening the
shutter, the operator moves the camera either toward or away from the
finger or skin to the point where the ridge detail is sharpest in the
ground glass. The camera is held firmly, the ground glass is removed,
the film is inserted and the photograph taken.

[Illustration: 402]

With respect to exposure time, it is possible only to generalize and
point out that each case will have its own individual aspects.
Controlling