Forensics Journal - Stevenson University 2011 | Page 58

STEVENSON UNIVERSITY

Upconversion versus non-magnetic powder

Upconversion versus magnetic powder

All of the substrates were allowed to age for a varying amount of
time before utilizing a non-magnetic powder (either black carbon
or white powder) for its comparison to upconversion powder. Four
trials with varying ages of fingerprints were conducted to compare
the non-magnetic powder to the upconversion powder. The best
quality print, based on an initial visual examination, was chosen on
each substrate and captured with the DCS-4. In the two week old
depletion series examined, fingerprints were captured on a black trash
bag, an evidence bag, a zippered sandwich bag, a PP sheet protector,
a fold top sandwich bag, and a black pebbled surface. The images of
the non-magnetic powdered side and the upconversion powdered side
were compared side-by-side. Of the substrates mentioned, none of
the upconversion powdered fingerprints were of the same quality as
the non-magnetic powdered side of the fingerprint captured. Figure
2 displays the side-by-side comparison of a two week old eccrine fingerprint developed on an evidence bag. The side developed with the
black powder exhibits better clarity as well as Level III detail. Level II
detail was only seen on the upconversion developed half.

All of the substrates were allowed to age for varying periods of time
before cyanoacrylate fuming and the utilization of magnetic powder
(either black or white magnetic) for its comparison to upconversion
powder. Four trials with varying ages of fingerprints were conducted
to compare magnetic powder to the upconversion powder. The 1
½ week old fingerprints were photographed and documented on a
polypropylene sheet protector, an evidence bag, and a red Coke can.
The background of the Coke can could not be suppressed enough to
obtain a clear image of the upconversion powdered side, leaving only
the magnetic half to be photographed.
Testing the two week old depletion series proved to be more successful in that over half of the substrates tested displayed excellent ridge
detail on both the magnetic and upconversion powdered halves.
Fingerprint images were captured on a zippered “Stor-it” bag, an
evidence bag, a fold top sandwich bag, a PP sheet protector, a black
pebbled surface, a black trash bag, and a PVC sheet protector. When
the two halves were combined for side-by-side comparison, magnetic
powder developed a clearer and more detailed fingerprint than the
upconversion powder. Figure 3 shows that the fingerprint developed
with the white magnetic powder on the trash bag afforded better clarity and detail in the ridges than the side developed with upconversion
powder. The upconversion treated half appears overdeveloped with
the powder unevenly distributed over the ridges of the print. For the
other ages of fingerprints the upconversion powder overdeveloped the
prints, rendering it difficult to capture the ridge details. Only the side
treated with magnetic powder was captured.

FIGURE 2: Print #1 of a two week old eccrine depletion series developed on an evidence bag. The left side is developed with black carbon
powder and the right side is developed with the upconversion powder.

FIGURE 3: Print #2 of a two week old sebaceous depletion series
developed on a black trash bag. The left side of the print was developed with white magnetic while the right side was developed with the
upconversion powder.

Fingerprints were captured on the white pebbled substrate for the
three week old depletion series; however, only the black carbon powdered side of this substrate was photographed due to the poor quality
of the upconversion powdered half. From the four week old depletion
series tested, only the black birthday bag had fingerprints developed
with enough quality t