INK SET, PRINTED ARTICLE, A METHOD OF PRINTING AND USE OF A COLORANT

摘要

The invention relates to an ink set comprising a plurality of inks of a firs t and of a second group, having different colors. Inks of said first group comprise a visible colorant and an additional IR-absorbing compound (IR- taggant) which has an absorption peak at a predetermined wavelength in the near infrared. Inks of said second group comprise a visible colorant which h as at the same time an infrared absorption peak at the same wavelength as that of the IR-taggant used in the inks of the first group. Preferred embodiment is a four-color process ink set comprising an IR feature.