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Rubber stamps: fake or genuine
How to distinguish
the fake from the genuine
Andrej Dvorsak - Private Investigator and Forensic Detective
So-called rubber
stamps, although these are actually made of silicone and other similar
materials, are still widespread both in business and private life. But
how does one distinguish genuine rubber stamps from fakes and what are
the techniques that forgers use to make forgeries? Such problems are
commonly encountered by private investigators and detectives who often have to deal
with cases involving forged papers and who know at least the basics of
the trade.
Nowadays it is very
easy to create a brand new duplicate of a rubber stamp with computer
technologies that are both accessible and prevalent in every high
street, but most forgers still use old techniques that are far from
sophisticated. One of the oldest is the so-called potato technique,
widely used by resistance movements during the Second World War in
Europe, and also in Nazi concentration camps. In Europe the ‘potato
technique’ is still in use.
The forger boils the
potato (not too much), and then cuts it down the middle. One part is
pressed on the genuine rubber stamp on the original document for a few
seconds to produce a ‘picture’ of the rubber stamp print on the
half-boiled potato. The potato is then pressed on to the fake document.
The result is a rubber stamp print with the same shape as the original,
but much brighter with an unclear picture and shapes. You can
distinguish the genuine and fake by their colours, which are thicker
(more condensed) on the genuine stamp. Also the lines and shapes are
much sharper on the original document. Under the microscope you can also
usually see some stains of starch on the surface of the document. The
starch can also be detected in a laboratory.
The same procedure has
also been employed by forgers using a fresh apple instead of a
half-boiled potato, and the egg technique was also popular among
forgers. They boiled an egg, peeled away the eggshell and rolled it over the
original rubber stamp on the genuine document. They then rolled the
imprinted egg over the fake document to establish a fairly good picture,
which was always very bright but with poor shapes, on the paper.
A more sophisticated
technique is to engrave the shapes of the original rubber stamp in flat
wood, slate, plastic and others hard materials. These fakes can be
distinguished very easily from the original. In most cases the falsifier
presses the engraving wood or plastic too strongly on the document so
that under the microscope the relief of the stamp can be discerned –
which is not the case for original rubber stamps which also typically
give quite different shapes of lines. Moreover, the different shapes and
sizes of engraved letters and pictures can lead to the conclusion that
the stamp has been faked. However, the most delicate and hardest to
prove are documents forged by modern techniques used on photocopies
(Photostats documents) and on documents »received« by facsimile machines.
The technique is very simple.
The falsifier makes a
scan of the original rubber stamp or a photostat of it on a transparent
film. Then this film is put over a document, so that the stamp is
positioned on the proper place. After that no special efforts are needed
to finalize the forged document; all that the falsifier has to do is to
push of the button on the facsimile or photostat machine. The faked
document and the layer (film) with the pre-copied stamp unite and make
one document, on which contains are all the details on their places.
Even an expert cannot, either with unaided eyes or with a usual
magnifying glass, distinguish the genuine from the forged photostat
»faxed« document.
Points to look for to establish that a rubber stamp is forged:
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Colours are
usually very bright
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The shapes
of letters and pictures are not sharp and often blurred.
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Proportion
between letters and other details of the stamp are different from those
in the original
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When the
stamp partially covers is over the picture or something alike, the stamp
could be slightly moved, so that the lines of it are broken on the edges
of the picture and the background foundation etc.
For all these first
steps on the field of examination a private investigator needs only a good
magnifying glass and a
handy ultra violet (UV) light. In the laboratory a document can be examined under the
different types of UV and infrared (IR) light, with microscopes and by means of
various other techniques including microphotography, computer scans,
chromatography etc., not techniques that the average private
investigator or private detective can employ himself.
In my practice I had
to examine the diploma degree of the University in pristine – Kosovo and
investigate it's authenticity. The
local contact send me the document from the University. On first glance
of inexperienced eye all was OK, including the rubber stamp.
However, the expert investigator can see some characteristics even with naked eye and under the
microscope and other instruments this characteristics became visible
also to everyone else. With computer techniques you can forge a document
and rubber stamp almost perfectly, but computer is not a friend of
criminals and always leaves a visible trace of the forgery for
investigators to discover.
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Picture 1
The stamp was suspicious also on first glance, because it has no
clear number and the name of faculty is missing.
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Picture 2
Under the microscope, here we used 17x magnification, you can
distinguish fake and genuine also by lines, which was made by ink
jet printer. Genuine rubber stamps have no such lines even under the
microscope.
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Picture 3
Detail under the 64x
magnification
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Picture 4
Sometimes it is necessary to check the document also with different
types of light. This picture was made under Infrared illumination.
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Picture 5
Same part of the document made by ultra violet light from behind the document.
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Picture 6
Same part of the document, but we used side light at a very acute
angle to the document.
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Picture 7
Same part of the document under the normal (North) light.
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NOTE: all pictures are from the archive of Andrej Dvorsak, made with VSC 2000 in
the Forensic lab
of Slovenian Ministry of Interior
Author: Andrej Dvorsak, B.A.
is a licensed private investigator, forensic detective and an expert of
document and handwriting analysis from Ljubljana, Slovenia. He is the
author of several books and scientific articles, among them the first
Slovenian manual for private detectives.
http://www.detektiv.si
http://www.detektiv-da.si
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