- Check bulbs, batteries, and lights.

- Center latents in opening of camera.

- Latent being photographed must be flush with opening of
camera.

- Outside light must be excluded.

- Include identification tag in photograph.

- Remove slide and pull safety tab of film pack before
making exposure.

- Hold camera still while making exposure.

- Pull correct number tab after each exposure (be careful
not to pull more than one).

- Do not use grained or uneven material as a backing when
photographing latents on transparent glass.

- Mirrors, polished chrome, and nickel plate will photograph
black in the fingerprint camera.

The foregoing has dealt with the standard use of the fingerprint
camera when the direct light afforded by the camera gives suitable
results. There will be cases, however, where the results from the use
of the direct light may not be adequate. Such cases may involve molded
or embedded prints, such as prints in putty, wax, soap, etc. Should
direct light give poor results, side lighting may prove effective.
This can be done by loosening two of the bulbs on one side so that
they will not light. The light given by the other two bulbs is
directed so as to pass at right angles, as much as possible, across
the ridges of the embedded latent print. Adjustment of the exposure
time must be made when this is done.

CHAPTER XVI

_Preparation of Fingerprint Charts for Court Testimony_

In testifying to fingerprint identification, the expert often prepares
charts to visually aid the court and jury in understanding the nature
of his testimony. Many times it is undoubtedly difficult for the
layman to perceive, from a vocal explanation alone, the full import of
an expert's testimony, due to its technical nature; consequently, some
graphic representation of the facts presented is amply justified and
rewarded. The preparation of the charts is ultimately the sole
responsibility of the expert using them. As a matter of interest to
law enforcement personnel engaged in fingerprint work, a brief
explanation of the preparation of such charts follows, along with
suggestions and remarks based on long experience in these matters.

To do the work conveniently, it will be necessary to have available,
in addition to the ordinary photographic developing and printing
materials, a projection enlarger which will enlarge preferably to at
lea