FIELD: information protection.
SUBSTANCE: group of inventions relates to a protective ink system, a method for obtaining it, and a method for assessing the authenticity of a protected document containing such a system. The protective ink system contains: i) substrate, ii) the first ink applied to at least part of at least one surface of substrate, while the specified first ink contains at least one IR-luminescent dye and/or at least one IR-luminescent pigment, and iii) the second non-luminescent ink applied to at least part of at least one surface of substrate, on which the first ink is applied, while the specified second ink contains at least one non-luminescent pigment absorbing IR radiation, and/or at least one non-luminescent dye absorbing IR radiation, while the specified first ink and the second ink overlap at least partially on at least one surface of the specified substrate, while the second ink is applied in the specified overlap area on top of the first ink, and the emission spectrum of the first ink and the absorption spectrum of the second ink overlap at least partially. The group of inventions is developed in independent and dependent formula clauses.
EFFECT: provision of a protected product, such as printed protected paper, such as a banknote or a verification certificate, which has an improved degree of protection against forgery, but at the same time the authenticity of which can be assessed in a simple way.
16 cl, 3 dwg
