| 摘要 |
FIELD: estimation of authenticity of documents, excise brands, bank-notes and securities. ^ SUBSTANCE: proposed compound is prepared by mixing gadolinium oxysulfide activated by terbium and yttrium oxysulfide activated by ytterbium and erbium. Size of crystal particles of said luminophores does not exceed 1.5 mcm. Compound thus prepared is introduced into printing ink and is applied on surface to be marked by letterpress printing method in form of mark which is invisible at common lighting. Mark is visualized by infra-red light source and/or ultraviolet radiation thus causing its green glow. Document is subjected to identification for estimation of its authenticity of falsification. Marking retains preset properties for extended period of time at high temperatures, bright light and high moisture content. ^ EFFECT: enhanced efficiency of protection against falsification. ^ 4 cl, 3 ex |
