Breaking NEWz you can
compiled by Jon Stimac
Match Results in Rape Indictment -
TIMES PICAYUNE, LA -
Jan. 23, 2004. ...a fingerprint match
that took four years to obtain has resulted in the indictment of a
man in a rape case...
Fear About Fingerprints
- ATLANTA JOURNAL-CONSTITUTION, GA
- Jan. 22, 2004 ...fingerprinting foreign
visitors may close the door on terrorists, but officials worry it
might also yank the welcome mat....
Man Freed in 1997 Shooting of Officer -
BOSTON GLOBE, MA
- Jan. 24, 2004
...Judge gives ruling after fingerprint
Man Accused in Dual
Slayings Caught in Ohio -
ATHENS BANNER-HERALD, GA - Jan. 22,
2004 ...suspect originally gave a fake
name, and his true identity was learned after his fingerprints were
run through AFIS...
Gary Pond passes on news regarding his
We are pleased to announce that we have just been added to the News Desk on the
opening page of the Photographic web site as at
We have also been told that the new Rolling Softie
160 will be shown in the new products section of the April issue of Peterson's
Laptop Magazine just featured us in their New Products section with an Elite
case and will show the Rolling Softie case the following month. We will
run a new 1/2 page ad in this publication.
Rangefinder, eDigital and others are also showing
new product information or writing articles about our newer Porter Cases.
Gary E. Pond, President
PORTER CASE, INC., South Bend, IN USA
(this is not a paid advertisement... I own one of Gary's cases, and it has been
a back-saver on many occasions!)
Last week, we looked at the future of AFIS and the fingerprint field.
This week, we look at some new research and a new product for the development of
latent prints on thermal paper. This week's Detail was obtained from
Manual of use for ThermaNin
paper, once mainly used as fax paper only, is now used in many applications.
These days it is used in ticket dispensers for giving out queue numbers or
parking tickets, in label printers, and printers for point-of-sales receipts at
retail shops like supermarkets.
Thermal paper turns black on application of heat (as in the printer) but also on
contact with polar solvents like alcohols, acetone, ether, ethyl acetate etc.
The regular solutions of fingerprint reagents like ninhydrin and DFO are either
based on a polar solvent (ninhydrin in ether or acetone for example) or rely on
certain amounts of these polar solvents to dissolve them when used in an apolar
bulk solvent like petroleum ether or heptane.
solutions have a detrimental effect on thermal paper: on application the paper
surface turns dark grey or black thereby obscuring any fingerprints that may
There are only a few techniques known for developing fingerprints on thermal
- 1,2-IND (as a 2 g/l solution in HFE-7100 containing 7%
ethyl acetate) has been reported to develop fingerprints without darkening the
top (active) layer of the thermal paper (John Stimac, Journal of Forensic
Identification, 2003, 53(3), 265-271). For finding and photographing the
developed prints a Polilight or similar light source is needed.
- DMAC (dimethylaminocinnamaldehyde) fumes react with
fingerprints on thermal paper (see e.g. Brennan et al., Journal of Forensic
Identification, 1995, 45(4), 373-380). The fluorescence of any developed
prints can be photographed with green light (Polilight, around 530 nm).
- Exposure to the fumes of concentrated hydrochlorid acid
was reported to develop prints on the top layer of thermal paper (Broniek,
Knaap, Journal of Forensic Identification, 2002, 52(4), 427-432). It will not
develop prints on the back of thermal paper.
- Treatment with a regular ninhydrin solution and after
allowing ample time for development of fingerprints, rinsing the paper with an
excess of acetone to remove all the text and/or grey-black stains.
These techniques may not be
appropriate, or the additional equipment needed not available.
Japanese researchers have published that hemiketals of ninhydrin, obtained by
exchanging the water molecule in ninhydrin [also known as 1,2,3-indantrione
monohydrate] for an alcohol, are soluble in apolar solvents like petroleum ether
without the need for addition of polar solvents. The solutions were reported to
develop fingerprints on thermal paper, without darkening of the surface.
Such a product (named ThermaNin) is now
To our knowledge, the effectiveness of the different techniques has not been
How does ThermaNin work
ThermaNin will not develop any fingerprints by itself. The process relies on the
fact that after application of its solution to paper, ThermaNin will readily
convert to ninhydrin and the alcohol upon contact with water present in the
paper or in the atmosphere. This conversion can be detected from the weak odor
of the alcohol that will be given off by the paper afterwards. The ninhydrin
will then be available to react with any fingerprint residue in the paper. The
ninhydrin will not dissolve in petroleum ether, so the paper can be dipped twice
(with a certain waiting time in between, to allow for the conversion of the
ninhydrin hemiketal to ninhydrin and alcohol) to increase the ninhydrin
concentration in the paper.
Manual of use
to the sensitivity of ninhydrin hemiketals (like ThermaNin) towards water, their
solutions in petroleum ether cannot be stored long without degrading the
performance. A working solution should be used soon, at least within 1-3 weeks.
Therefore, we cannot supply working solutions, they should be made fresh when
needed. The ThermaNin crystals that we supply are fairly resistant to
atmospheric humidity and have no apparent shelf life when stored in tightly
A working solution that takes not too long to prepare, by dissolving the
ThermaNin powder in petroleum ether/pentane or heptane by shaking (for 5-10
minutes), contains 4 gram per liter (or 0.4 gram per 100 ml). Slight warming of
the solution (till around 30-40° C) will aid the dissolution of the ThermaNin
researchers at the BKA in Wiesbaden found that for dissolving, application and
storage of working solutions of ninhydrin hemiketals either plastic or aluminium
containers should be used, with a strong preference for aluminium. Generally
speaking petroleum ether etc. diffuses out of plastic bottles and water in,
aluminium does not have this problem.
In glass bottles the shelf life of the working solutions is drastically
shortened. This is probably due to the small amount of water adhering to the
walls and the slightly acidic nature of the glass surface (accelerates the
reaction between water and ThermaNin).
Development of the fingerprints can be done in the usual manner: at room
temperature, in the dark and elevated humidity (around 80% is preferred).
Because of the nature of thermal paper heating of the paper to accelerate
development of the prints is not possible: the paper will turn dark.
Because of the sensitivity of the paper for polar solvents, treatment of the
thermal paper with zinc chloride is not an option either.
On contact with water ThermaNin will readily fall apart in ninhydrin and
alcohol. Therefore, the safety characteristics of the product can be judged from
those components. Ninhydrin is considered harmful if swallowed and irritating to
eyes, skin and respiratory system; the alcohol as a skin and eye irritant. The
precautions taken when working with ninhydrin (protective clothing, gloves,
safety glasses when working with the solutions) will be sufficient for this
To discuss this Weekly Detail, log on to the CLPEX.com
message board: (http://www.clpex.com/phpBB/viewforum.php?f=2)
More formal latent print discussions are available at
(I reproduced this here because I could sure
stand to follow this advice!...)
Learn to say 'No' with grace
A colleague has just asked you to work on a time-consuming project, and you
would like to decline gracefully. Here's how:
1) Beware the automatic "Yes." You may hate to flatly turn somebody
down, but remember it's much harder to get out of something you've already
agreed to than to turn it down immediately.
2) Buy time. Unless you're already certain of your response, ask
for time to think about it. That is both a reasoable and truthful
3) Be direct. If the answer is "No," say "No." Say it
respectfully, but say it. Example: "I'm really flattered that you'd think
of me. But I'm going to have to turn the opportunity down." And
then, be quiet. Avoid the impulse to give a list of reasons. That
will only open the issue for discussion and give your colleague an opportunity
to talk you out of your decision.
Management, Marshall, J. Cook, text from the November 2003 issue of
Communication Briefings, briefings.com.
UPDATES ON CLPEX.com
Updated the Bookstore with sold items; I
will be adding a few new items this week (for real this time!) for posting next
Updated the Newzroom
Feel free to pass The Detail along to other
examiners. This is a free newsletter FOR latent print examiners, BY latent
print examiners. There are no copyrights on The Detail, and the website is open
for all to visit.
If you have not yet signed up to receive the Weekly Detail in YOUR e-mail inbox,
go ahead and join the list now
so you don't miss out! (To join this free e-mail newsletter, send a blank
firstname.lastname@example.org ) Members may
unsubscribe at any time. If you have difficulties with the sign-up process
or have been inadvertently removed from the list, e-mail me personally at
email@example.com and I will try
to work things out.
Until next Monday morning, don't work too hard or too little.
Have a GREAT week!