Apparatus for conducting secondary tests for security validation are presented. In one embodiment of the invention a light source, either infrared or visible, is cast upon two neighboring areas of a paper purported to be a valid instrument, these areas being of different light reflective characteristics....http://www.google.fr/patents/US4127328?utm_source=gb-gplus-shareBrevet US4127328 - Apparatus for conducting secondary tests for security validation
Apparatus for conducting secondary tests for security validation
