Security paper with authentication features

摘要

A security paper has incorporated or imprinted authentication features which are ferromagnetic and also have only low absorption in the infrared region of the spectrum. The existence of the two properties is tested at the same point in the security paper, the two tests preferably being carried out simultaneously. Substances which have this rare combination of properties include a few ferrites, ferromagnetic garnet compounds and the so-called green ferromagnetic compounds.