cess of taking fingerprints. The upper 10 prints
are taken individually--thumb, index, middle, ring, and little fingers
of each hand in the order named. These are called "rolled"
impressions, the fingers being rolled from side to side in order to
obtain all available ridge detail. The smaller impressions at the
bottom of the card are taken by simultaneously printing all of the
fingers of each hand and then the thumb without rolling. These are
called "plain" or "fixed" impressions and are used as a check upon the
sequence and accuracy of the rolled impressions. Rolled impressions
must be taken carefully in order to insure that an accurate
fingerprint classification can be obtained by examination of the
various patterns. It is also necessary that each focal point (cores
and all deltas) be clearly printed in order that accurate ridge counts
and tracings may be obtained.

In preparing to take a set of fingerprints, a small daub of ink should
be placed on the inking glass or slab and thoroughly rolled until a
very thin, even film covers the entire surface. The subject should
stand in front of and at forearm's length from the inking plate. In
taking the rolled impressions, the side of the bulb of the finger is
placed upon the inking plate and the finger is rolled to the other
side until it faces the opposite direction. Care should be exercised
so the bulb of each finger is inked evenly from the tip to below the
first joint. By pressing the finger lightly on the card and rolling in
exactly the same manner, a clear rolled impression of the finger
surface may be obtained. It is better to ink and print each finger
separately beginning with the right thumb and then, in order, the
index, middle, ring, and little fingers. (Stamp pad ink, printing ink,
ordinary writing ink, or other colored inks are not suitable for use
in fingerprint work as they are too light or thin and do not dry
quickly.)

If consideration is given the anatomical or bony structure of the
forearm when taking rolled impressions, more uniform impressions will
be obtained. The two principal bones of the forearm are known as the
radius and the ulna, the former being on the thumb side and the latter
on the little finger side of the arm. As suggested by its name, the
radius bone revolves freely about the ulna as a spoke of a wheel about
the hub. In order to take advantage of the natural movement in making
finger impressions, the hand should be rotated from the awkwar