T H E
D E T A I L
Monday, October 6, 2003
BREAKING NEWz you can
compiled by Jon Stimac
New Concerns Over Fingerprinting
- The Sunday Herald,
- October 5, 2003
independent examiners refute a new SCRO case, saying the identified print
was "unsafe" and "not sufficient to be positively identified"...
Thumbs Down on
Prints -WINNIPEG SUN, CANADA -
Oct. 2, 2003 Commentary on the
Manitobans having to provide fingerprints for
their driver's licenses...
Officers Get Refresher Course In Fingerprinting-
HOMETOWN CHANNEL.COM, AR
- Oct. 2, 2003
Oklahoma police officers should now feel more confident in their ability to
Going High-tech for Prints - TROY
MESSENGER, AL - Oct.2, 2003
Pike County Jail has been implementing new technology to fingerprint newcomers
to the jail and corrections officers...
Judge OKs More
Fingertip and Palm Prints - SAUK
VALLEY NEWSPAPERS, IL
- Sept. 30, 2003
Il Judge ruled that more inked prints of fingertips and palms could be
taken of the man who is charged with first-degree murder...
Good morning via the "Detail," a weekly e-mail newsletter that greets
latent print examiners around the globe every Monday morning. The purpose of the
Detail is to help keep you informed of the current state of affairs in the
latent print community, to provide an avenue to circulate original
fingerprint-related articles, and to announce important events as they happen in
Last week, we re-published
"The Myth of Fingerprints", by Michael Cherry. This week, we realize that
Michael Cherry is a regular reader of the Weekly Detail, and he provides us with
his supplemental comments on his article published last week.
Good morning, and thank you for taking a moment to
read my comments regarding my article "The Myth of Fingerprints." I asked Kasey
to publish this because I feel strongly about this subject, and I sincerely
desire for everyone to know the reasons behind the article.
Even though I have some training and knowledge of fingerprints, you will not see
me testify as a fingerprint expert. I am not a fingerprint expert, and I would
never claim to be a fingerprint expert. Likewise, I would not expect to see
someone testify to the results of a fingerprint enhancement unless at a minimum,
they understood the analog to digital and digital to analog conversions that
took place as well as the strengths and weaknesses of the equipment used.
Some examiners may have no choice, if they want to keep their jobs. They may be
required to present an altered image in court. The bottom line is this: If I
produced a second enhanced version of the same latent fingerprint in a case and
you were asked which enhanced fingerprint is the correct one; Unless you are
both a fingerprint expert and an imaging expert your answer would be "I do not
My intent is not to disrespect the value and contribution of fingerprint
examiners. My intent is to improve the quality of the equipment and procedures
used to perform fingerprint enhancement. But why would anyone budget money for
training or improved equipment if a fingerprint enhancement case has never been
seriously challenged in court?
As many of you know, I was involved in Reyes v Florida. Every day, fingerprints
are routinely enhanced, yet there have been no fingerprint enhancement
challenges since Reyes. And to provide a level of comfort for now... even though
the tone of my NACDL article is a call-to-arms, I have not yet received even one
inquiry from a defense attorney or public defender’s office. And I have heard
estimates that criminal defense attorneys loose between 90 and 95% of their
I have also asked Kasey to distribute my other article, "Reasons to Challenge
Digital Evidence and Electronic Photography."
If you have any questions or interest, please don't hesitate to contact me as
some already have. If we get enough responses, perhaps we can conduct a training
Reasons to Challenge Digital Evidence and Electronic Photography
by Michael Cherry
Originally written for the NACDL Champion; reprinted here with permission of the
02 June 2003
If digital evidence can be incorrectly altered or enhanced1 by newly
trained personnel, and digital cameras2 and printers3 are
not equal to their film counterparts in quality and color, what does that say
about the quality of today’s forensic evidence which is transitioning to
Examples of digital concerns:
• Digital cameras do not accurately represent color.
• Dye-sublimate digital printers can even confuse imaging experts. They cannot
produce the highly accurate photographic images that film does, but their images
appear to be photographs. They produce color and negative prints on photographic
style paper that mimics the look and feel of photographs.
• In many instances, the digital printer used is not as accurate as the digital
camera used, and therefore crime scene details and fingerprint minutiae is lost.
• The law enforcement community is incorrect regarding the acceptability of
using traditional darkroom enhancement techniques on digital images
“…Traditional enhancement techniques are techniques that have direct
counterparts in traditional darkrooms. They include brightness and contrast
adjustment, color balancing, cropping, and dodging and burning.
These traditional and acceptable forensic techniques are used to achieve an
accurate recording of an event or object4.” Many different forms of
image enhancement and traditional darkroom image enhancement can render some
crime scene details and fingerprint minutiae unprintable. For example,
Dodge-and-burn, the selective lighting and darkening of areas within an image,
can place details outside of the threshold of a digital printer’s range of light
and dark printing capabilities.
• The law enforcement community is incorrect with regard to the discovery of
image enhancement. “Question: is it necessary to document the enhancement
process used to produce an enhanced image? Answer: the need to document the
enhancement process is determined by the process used. Discussion: documentation
of enhancement steps is not necessary when using traditional darkroom techniques4.”
• The transition to digital images requires a brand new level of standards,
guidelines and training. For example, the use of image editing and enhancement
software should be curtailed or at least regulated. Before and after images
should be routinely provided. This is essential when the original evidence is
not is not available or well preserved. Examples include hard to- lift
fingerprints, footprints, bite marks and tire patterns.
• There are known quality problems associated with some digital printers,
scanners and cameras. For example, some digital printers are famous for their
fading pictures, others for their magenta cast.
• Digital images should be challenged when the original image is not available
for comparison. Examples; include hard-to-lift fingerprints, footprints, bite
marks and tire patterns. There are many reasons to challenge including
authenticity, accuracy and the quality of hacker-free security procedures.
• Digital images should not be compressed to save space unless a loss-free
method is used.
• All enhancements should be challenged, as they require very precise steps and
newly trained personnel may find them difficult to understand or implement. This
is particularly true of audio, video and fingerprint enhancements. Enhancements
of enhancements should be regulated. There is a relevant challenge for any form
of digital image or digital enhancement associated with audio, video and
The Iowa International Association for Identification (IAI) Web site highlights
State v. Hayden, 950 P.2d 1024 (Wash. App. 1998),where the Washington court of
appeals noted experts’ claims “that digital photographs are superior to regular
film photographs because digital photographs can pick up and differentiate
between many more colors and shades of gray than film photographs. Digital
cameras do not accurately represent color.
I did not realize how rapidly the criminal forensics community was transitioning
to the use of digital technology until I watched CBS News 60 Minutes II the
Hidden Clue, “Detectives now have a new tool for cracking even the toughest of
cases,” Jim Stewart reports. “Known as digital fingerprint enhancement, it’s
become the silver bullet among police forensic units all across the country……..”5
As a voting member of the evidentiary committee of The Association for
Information and Image Management (AIIM)6 and a pioneer in image
management and digital photography going back to early NASA days, I know it’s
very difficult to perform a proper enhancement, particularly a fingerprint
Digital enhancement is highly controversial within the imaging community. The
product of a digital enhancement is a new image which is identical to old one,
except for its altered characteristics. For example, the red car image now has a
twin, a blue car image.
In the courtroom enhanced digital images are original images that have undergone
some computer changes, and it falls to the discretion of a trial judge as to
whether they are admissible as duplicates. I would like to classify enhanced
digital images as enhanced digital images and not as originals or duplicates. I
would also like to number enhanced images to readily identify their lineage.
An image derived from the source image would we a first order enhancement, an
image derived from that image would be a second order enhancement and so on. As
two or more enhanced images can be spawned from the source image, I would like
to see them alphabetized e.g. image 2a and image 2b.
Mathematical enhancements include: magnification, color substitution and the
removal of a thin nylon stocking or mask covering the features of a persons
face. After removal, the nose shape, chin type and the presence or absence of a
mustache or beard can often be determined.
Mathematical enhancements can be quite powerful. Unfortunately, it is not
uncommon for mathematical enhancements to be performed incorrectly as we are in
a transitional period from analog to digital.
Artistic enhancements can be used to do anything: selectively darken or lighten
areas within an image (Dodge and Burn), place a person within a picture or video
as well as to modify conversations within an audio or video recording. Artistic
enhancement can lead to pure fantasy.
All enhancements should be challenged as they require very precise steps and
newly trained personnel may find them difficult to understand or implement. This
is particularly true of the audio, video and fingerprint enhancements. In
addition it is not uncommon to see artistic and mathematical enhancements on the
same newly created image.
On the positive side, scientists are having some success in enhancing low
quality videotape commonly found in gas stations and convenience stores. While
not necessarily ready for the courtroom, the results of these improvements can
be very useful in determining the probable absence or presence of a specific
Some concluding thoughts:
• Are there known quality problems associated with the digital printer, scanner
or camera used?
• If enhanced images are introduced, were the enhancements correctly done? Can
they be repeated using a different person?
• Enhancements of enhancements shouldn’t be allowed as they are unnecessarily
• Digitally enhanced pictures should be identified as such.
• If digital images are compressed was a loss-free method used? If not, why not?
• Digital images should be challenged when the original image is not available
• During today’s cost-driven transition period to digital, both the quality of
the images and the experts tend to be inferior to their analog counterparts.
• Text files that describe the evidence should be properly safeguarded.
1 The product of a digital enhancement is a new image which is identical to old
one, except for its altered characteristics. For example, the red car image now
has a twin, a blue car image.
2 Kodak T-MAX 100 can resolve approximately 200 line pair per mm TOC 1000:1,
Kodak Web Site, 200 pixels/mm at 35mm resolution 36*200*24*200=34,560,000 or 34
Megapixels In conventional digital cameras systems, color filters are applied to
a single layer of photodetectors in a tilted mosaic pattern. The filters let
only one wavelength of light - red, green or blue - pass through to any given
pixel, allowing it record only one color. As a result, typical mosaic sensors
capture 50% of the green and only 25% of each of the blue and red light. The
approach has inherent drawbacks, no matter how many pixels a mosaic-based image
sensor might contain. Since they only capture one third of the color,
mosaic-based image sensors must rely on complex processing to interpolate the
two-thirds they miss. Not only does this slow down the speed of image rendering,
interpolation also leads to color artifacts and a loss of image detail. Some
cameras even intentionally blur pictures to reduce color artifacts.
3 Computer printers print at 300 to 2400 dots per inch. Film requires at least
8000 dots per inch. Sales terminology can be misleading, 4800 and 5760 optimized
dots per inch (dpi) are used to describe printers that i mprove the appearance
of basic 1200 x 1200 dpi images. These printers can not accurately print 4800 or
5760 dpi input images. Some drum scanners can scan 35mm film at 11,000 dpi. (Bob
Myers, Heidelberg USA, Inc.)
4 The National Association of Criminal Defense Lawyers, Inc. (NACDL) Standards
and Guidelines, Recommendations and Guidelines for the Use of Digital Image
Processing in the Criminal Justice System Scientific Working Group on Imaging
Technologies (SWGIT) Version 1.2, June 2002.
5 The product of a digital enhancement is an identical twin image, except for
its altered characteristics. Examples include a red gun instead of a blue gun or
the removal of an extraneous pattern, the weave of a bed sheet, to make the new
fingerprint image more apparent.
6 AIIM holds the secretariat for International Standards Organization (ISO) ISO/TC
171 SC2, Document Imaging Applications, Application Issues. AIIM is also the
administrator for the U. S. Technical Advisory Group (TAG) to ISO TC 171,
Document Imaging Applications that represents the United States at international
meetings. Over 80 of AIIM's standards, recommended practices and technical
reports have been drafted and approved by the American National Standards
About the Author
Michael Cherry, is a principal in GMC7 Inc. He assisted NASA in the development
of imaging displays used by the Apollo Moon Flight Simulator for Celestial
Navigation. He worked with Lou Cataldo, to automate his early single fingerprint
system. He collaborated with Sony Labs in the development of color imaging
products and he joined with IBM Imaging Labs in numerous efforts including the
capture and display of digital camera images. He has published articles for the
US National Institute of Standards and Technology (NIST). He is a Giga expert
and a voting member of the evidentiary committee of The Association for
Information and Image Management (AIIM).
51 Saddle River Road
Woodcliff Lake, NJ 07677
Copyright © 2003, The National Association of Criminal Defense Lawyers, Inc. (NACDL)
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