PRINTING INK ITS USE FOR THE AUTHENTICATION OF ARTICLES ARTICLES OBTAINED THEREBY AND AUTHENTICATION METHODS

摘要

A printing ink comprising a first fluorescent dye acting as donor and a second fluorescent dye acting as acceptor is described. The first fluorescent dye upon excitation by electromagnetic radiation falling within an excitation wavelength range of the first fluorescent dye is capable of emitting electromagnetic radiation in at least one first emission wavelength range said first emission wavelength range of the first fluorescent dye overlapping with at least one excitation wavelength range of the second fluorescent dye to thereby excite the second fluorescent dye to emit electromagnetic radiation in a second emission wavelength range .