Method and ink sets for marking and authenticating articles
First Claim
1. A printing ink, comprisinga) at least one dye or pigment having at least one absorption maximum in the visible range of the electromagnetic spectrum which is substantially different from the absorption maxima of the base colors of the CIEXYZ system, andb) at least one other dye or pigment having an absorption band in the visible range of the electromagnetic spectrum whose band width at half intensity is narrower than 2400 cm−
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Accused Products
Abstract
The invention discloses a method for marking and authenticating a security article, such as a banknote, a document, a ticket, a foil, a thread, a label, a card, or a commercial good, so as to provide for an easy authentication of said article by a machine, such as a currency acceptor, a ticket validator, or a hand-held authentication device. According to the disclosed method, the security article carries a marking in the form of a user-defined design, wherein said marking comprises dyes or pigments belonging to an extended, or hyperchromic color space which is not reproducible by commercially available, 4-color desktop reproduction equipment. The authentication of said marking includes the mathematical transformation of the crude spectral information to statistically independent hyper-color coordinates, and the comparison of selected hyper-color coordinates with corresponding reference values.
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Citations
23 Claims
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1. A printing ink, comprising
a) at least one dye or pigment having at least one absorption maximum in the visible range of the electromagnetic spectrum which is substantially different from the absorption maxima of the base colors of the CIEXYZ system, and b) at least one other dye or pigment having an absorption band in the visible range of the electromagnetic spectrum whose band width at half intensity is narrower than 2400 cm− - 1, and
c) at least one other dye or pigment having at least one absorption maximum in the ultraviolet or in the infrared region. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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Specification