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.
Paper
Features
For each currency produced a corresponding paper is manufactured.
Banknote paper is made from cotton pulp which gives it better
durability than commercial papers and a very distinctive feel.
Much of the time, it is the initial 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 commercial 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 thicknesses of paper, with
light areas of the watermark being a result of thinner paper.
The highlighted effect of " ultra 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
e.g microprinting on a transparent plastic thread or adding
materials so they fluoresce under ultraviolet 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 iridescent 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 window of transparency and pseudo watermarks
are produced by printing additional designs in opaque white
These features offer good protection from colour copier counterfeiting
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