opening of the
camera. This is accomplished by opening the angular front section of
the camera after the metal plate covering the front has been opened,
and setting the aperture over the latent impressions so that they will
be as near the center as possible. Then, holding the camera firmly in
place, it is carefully closed (fig. 427).

During exposure the camera must be held perfectly still. Any movement
of the camera or object will result in a fuzzy or double image.

In photographing a small, movable object such as a bottle or tumbler,
the camera should not be placed on its end and an attempt made to
balance the object across the opening. Instead, the camera should be
placed on its side and the bottle or tumbler built up to the opening
so that there is no necessity for holding the object (fig. 428). There
will be, of course, instances where the camera will have to be held,
such as to the side of a wall, cabinet or automobile. Here an extreme
effort should be made to avoid moving the camera or permitting it to
slip during exposure.

[Illustration: 427. Centering of latent in aperture insures equal
distribution of light over print.]

Anticipating the possible use of the photographic negatives in a court
proceeding, it becomes of paramount importance to be able to identify
them. This is done by using what is called an identification tag. The
tag consists of a small piece of paper bearing the date, initials of
the examiner, and possibly a case number, and it should be
hand-written. The tag is placed near the latent prints being
photographed so that it will appear in the picture. It should be borne
in mind that concentration should be on the latent impressions, which
must be centered, and the identification tag should be to one side and
not covering any of the latent prints. Another method of
identification, if the surface permits, is to write the
above-mentioned data on the surface of the object bearing the latents
so that the information set out will also be a part of the picture.
Too much emphasis cannot be placed on the importance of the
identification tag. The lack of such data, by discretion of the
court, may exclude the latents as evidence, in the absence of the
original specimen bearing the latents.

[Illustration: 428. In photographing objects with curved or irregular
surfaces, camera should be laid flat and latent-bearing surface built
up to opening.]

The following are suggested exposure times for Tri-X f