VALUABLE DOCUMENT PROTECTED AGAINST FORGERY AND METHOD OF DETERMINING ITS AUTHENTICITY Russian patent published in 2014 - IPC D21H21/40 B41M3/14 

FIELD: printing.

SUBSTANCE: invention relates to the field of protection of valuable documents against forgery. The valuable document comprises on its surface an invisible protective marking applied on the elongated section along the long side of the document, which is intended for the instrument reading. The protective marking has the property of selective absorption of the radiation in the range optical spectrum from 0.76 mcm to 10 mcm. The marking is wholly or partially located in the area of additional masking marking. The material of the latter has the property of re-radiation when exposed of the exciting radiation of the same spectral composition as the material of the protective marking, but is characterised with magnitude of afterglow time. The method of determining the authenticity of the valuable document comprises revealing the hidden security marking on the valuable document. The revealing of marking is carried out by registration of afterglow of its material after removal of the exciting radiation and/or by registration of the diffuse reflection of the material in the optical range of wavelengths from 0.76 mcm to 10 mcm. Violation of the predetermined information indicates full or partial forgery.

EFFECT: increase in the level of protection of the valuable document against forgery.

13 cl, 4 ex