hat when the ridge detail does not show on the surface of
the outer skin the underside should be examined, for many times the
detail can be seen clearly. Should this be true, of course, the
underside is photographed.
In cases where it is noted that the outer skin is gone and the finger
is not saturated with water, it is possible to dry the surface
sufficiently for inking and printing purposes by rolling the finger on
a blotter. If this fails, the finger is wiped off with a piece of
cloth which has been saturated with alcohol, benzine or acetone, after
which it may be inked and printed.
_Drying the fingers_
In many instances it will be found that the outer skin is gone and the
fingers themselves are saturated with water. A quick method of drying
out the fingers is to place them in full strength acetone for
approximately 30 minutes. The fingers are then placed in xylene for
about an hour or until the xylene has overcome the reaction of the
acetone. After removal from the xylene the fingers should be placed on
a blotter until the surface of the fingers appears dry. They are then
ready to be inked and printed.
It will be noted in this procedure that when the fingers are removed
from the acetone they dry and harden in a matter of seconds. The
purpose of the xylene is to resoften the fingers. After this
treatment, should the resulting inked impressions be unsuitable for
classification purposes, the ridge detail should be photographed.
_X-ray photography_
The use of X-ray photographs (radiography) has been advocated by some
for purposes of recording the ridge details in decomposed, desiccated,
or macerated cases. Briefly, the procedure involves the covering of
the fingers with heavy salts such as bismuth or lead carbonate, in a
thin, even film over the pattern area and then, by the use of the
X-ray, reproducing the ridge detail. This procedure necessitates the
use of X-ray equipment and a technician skilled in making radiographs.
It is, therefore, an expensive operation. The results of the
radiograph in no way compensate for the expense, time, and skill
required inasmuch as in those cases where many wrinkles and creases
appear in the fingers, especially desiccated specimens, the results
have been very poor. In instances where there are no wrinkles or only
a few, and where the creases are not too deep, the ridge detail is
reproduced very well in the radiograph. In these cases, however, it is
usually possible t
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