Breaking NEWz you can UzE...
compiled by Jon Stimac
NYPD Fingers Fingerprint Computer –
NEWSDAY, NY - Sept. 4, 2004
...a day after the city was held in
contempt for detaining convention protesters, police claim the
state's fingerprint computer caused the problems...
Protest Arrests Put Fingerprints in File –
ALBANY TIMES UNION, NY - Sept. 3, 2004
...a consequence of the nearly 2,000
arrested convention protesters has been the additional volume of
fingerprints for processing...
Fingerprints Don't Lie –
PIONEER PRESS, IL -
Sept. 2, 2004 ...city board
members approved the purchase of a Live Scan fingerprinting device,
printer, software and photo equipment...
Judge Denies Motion to Hire Fingerprint Expert –
PARKSBURG NEWS, WV - Aug. 31, 2004
...a motion to hire a fingerprint
expert in a burglary trial was recently denied by a Wood County
Circuit Court Judge...
we took a philosophical look at encouragement, the "little things" and level 3
Jennifer Hannaford shares an example of a friction ridge recording that we
should all be aware of.
Anomalies of Livescan Capture
“The goal that is to be addressed in any situation is to obtain a recording
of the friction ridge skin that is of adequate quality for the comparisons that
are subsequently to be made. Ideally, such prints will have good contrast,
clear detail, and be complete.” - Cowger
The history of exemplar capture for latent prints has mainly stressed the three
main points listed above:
Perhaps, there is another criterion to consider; accuracy.
With the ever growing and popular use of digital technology, the acquisition of
exemplar prints using livescan should be explored and understood by latent print
examiners. How accurately does this technology convey the spatial relationship
of details within the friction ridge skin? How accurately does this technology
depict the existing minutiae in the represented friction ridge?
Individuals within the fingerprint community need no reminder of the principles
upon which the individualization through the use of fingerprints is based. Yet,
a statement of these points will emphasize the importance of the information
upon which we rely when using any standard for a comparison:
Friction ridges are permanent. Friction ridges are permanently
formed during fetal development and remain the same, barring scarring or
amputation, until death and decomposition sets in.
Friction ridge formations are unique. No two areas of friction
ridge skin are the same on two different people, identical twins or on two areas
of friction ridge surfaces upon the same person.
If there are areas of dissimilarity that cannot be explained,
the origin is not the same.
Thus, upon any capture of the friction ridge information,
whether it be a latent or an exemplar, the impression will demonstrate the
uniqueness of that friction ridge skin in the manner that it exists.
Throughout my experience as a latent print examiner I have conducted many
comparisons. I have used exemplars/standards that have varied in their methods
of capture. They have included traditional printer’s ink, modern ink methods,
photocopies of these varieties and livescan images. Recently, a routine
comparison using a set of livescan exemplars caught my attention.
Did these prints originate from the same area of friction ridge skin?
What about the one-dissimilarity doctrine?
“A doctrine has emerged in fingerprint comparison...if two fingerprints differ
in a single ridge characteristic the prints cannot be attributed to the same
finger or individual.”-Thornton
In fact, these two examples originated from the same area of friction ridge
skin, both images reside on the same card, and they were captured during a
single exemplar recovery event.
The example on the left is the rolled image of the right middle finger. The
image on the right is the right middle finger captured as the flat. During
comparison of a latent of limited detail to the rolled impression in the above
example, I concluded that the whorl I was examining could not have originated
from this individual. The conclusion was based on a single bifurcation present
at the core of the latent to the double bifurcation arrangement in the
corresponding area at the core in the exemplar. Upon closer inspection of the
exemplar set, it was determined that this individual could not be eliminated.
The information between the flat and the rolled impression, although originating
from the same area of friction ridge skin, did not agree.
After this experience, I have taken a closer look at the livescan images I use
for comparisons and have noticed similar anomalies. In addition to inaccurate
capture of detail, I have observed what appears to be a distortion of the
spatial relationship of minutiae.
To this point, I have only observed artifact and distortion within the rolled
exemplar images. So, what is the mechanism behind the occurrence? I am not an
expert in digital technology, nor do I have any experience operating a livescan
system. However, by personal observation, I offer a possibility as an
explanation. There appears to be a double or repeated capture of friction ridge
skin in the final image. This may occur from slippage, hesitation or changes in
pressure of the finger being rolled on the platen surface during capture,
obscuring the information. Although the area recaptured is very small, the
additional information may blend with the rest of the print, causing extra
detail to appear natural within the impression. One has to wonder if this is an
operator issue, an instrument issue or a combination of both. Regardless of the
mechanism, the fact remains that this phenomenon has been documented, and the
presence of artifact may be subtle enough to go undetected (especially if it is
a condition the viewer is not actively looking for).
The intention of this communication is to share with the fingerprint community
the possibilities that one might encounter when using livescan images. Each
examiner should strive to understand what is being examined and be prepared to
explain this type of distortion if it needs to be addressed in court.
What other effects might an artifact in a livescan image have on the comparison
process? Could an artifact in the exemplar lead to an erroneous elimination?
The example given above supports the possibility when one is provided with
limited information in a partial latent print. But, could the converse be
true? Could an erroneous identification occur? No. Just as uniqueness of
friction skin is established through the random biological development of ridge
detail, a random arrangement achieved digitally can not recreate the uniqueness
of any another area of friction ridge skin.
Examiners may ask themselves if this medium is reliable if the possibility of
artifact exists. It is reliable, with the caveat that one must be aware of the
possibility of the existence of anomalies. Moreover, correspondence of detail
within an image can be determined and confirmed through comparison of the rolled
and flat impressions.
I hope to continue exploring this topic and encourage those who find unusual
conditions, found in any capture medium, to share them with the Latent Print
Examiners at the Vermont Forensic Laboratory. I can be reached directly by
To discuss this Detail, the
message board is always open: (http://www.clpex.com/phpBB/viewforum.php?f=2)
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