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Security
thread:
Security
thread
is a
thin thread or ribbon running through a bank note
substrate. All 1990 series and later notes, except the
$1, include this feature. The note’s denomination is
printed on the thread. In addition, the threads of the
new $20 and new $50 have graphics in addition to the
printed denomination. The denomination number appears in
the star field of the flag printed on the thread. The
thread in the new notes glows when held under a
long-wave ultraviolet light. Since it is visible in
transmitted light, but not in reflected light, the
thread is difficult to copy with a color copier which
uses reflected light to generate an image. Using a
unique thread position for each denomination guards
against certain counterfeit techniques, such as
bleaching ink off a lower denomination and using the
paper to "reprint" the bill as a higher value
note. |
