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Substrate Features
Substrate features are an integral
part of the material on which the bank notes are printed .... why not
call them paper features? Well some bank notes, such as the Australian
Dollar, are printed on plastic! The choice of substrate is very important
as it has to be a very durable material resistant to tearing, withstanding
crumpling and stable to environmental effects such as humidity.
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Learn about the following topics:
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Paper Features
For each currency produced a corresponding
paper is manufactured. Banknote paper is made from cotton pulp which gives
it better durability than commerical papers and a very distinctive feel.
Very often it is the inital feel of a counterfeit that urges someone to
have a closer look at what they are holding. If bank note paper is held
under ultra violet light it is dull compared to commerical papers.
The paper manufacturing process allows for a number of features to be
created.
Watermark
The watermark is one of the most obvious
security features of a paper banknote. When held up to the light an image 
can be seen in the paper, usually a portrait similar to that printed on
the note.
The image of the watermark is caused by different thickness of paper,
with light areas of the watermark being a result of less paper.
The highlighted effect of "thin" paper is sometimes used as an added security
effect in small specific areas within a watermark, e.g. A denomination
may appear as a "highlighted" portion compared to the main bulk of the
watermark.
A watermark is an excellent security feature. A counterfeiter is very
unlikely to manufacture his own paper. Having said that there are some
ways watermarks can be simulated although the effects are crude.
Threads
  Threads
are embedded within the paper fibre and can be completely invisible or have
a star burst effect, where the thread appears to weave in and out of the
paper when viewed from one side. However when held up to the light the thread
will always appear as a solid line. Features can be built into the thread
material themselves e.g microprinting on a transparent plastic thread or
adding materials so they fluoresce under ultra violet light. The thread
is a difficult feature to counterfeit but some counterfeiters have been
known to print a thin grey line or a thin line of varnish in the area of
the thread.
Other Embedded Features
While the paper is in the pulp stage various elements can be added that
then become embedded in the paper in a random fashion. e.g Tiny fibres
which fluoresce under ultra violet light or tiny irridescent foils known
as planchettes. It is also possible to tint the paper.
Plastic
A plastic substrate has been adopted
by some countries as the chosen medium for their currency. Security features
are built into the plastic is coating with an opaque white leaving a windows
of transparency and pseudo watermarks are produced by printing additional
designs in opaque white These features offer good protection from Color
copier counterfeiting.
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