| 摘要 |
It is based on the use of two types of inks, specifically two inks with different formulations, one with pigments transparent to infrared TIR and another with pigments not transparent to infrared NOTIR. With these two ink formulations, two successive impressions of the document are made, one with each type of ink, so that when, subsequently, the document is exposed to analysis by a suitable infrared detector, part of the impression will be visible using the detector and another part will not be visible. The part that is visible by means of the detector may be made to correspond to any appropriate code, practically without limit in this respect, from a simple word such as, for example, the word "ORIGINAL", to a complex bar code which allows, with the collaboration of a decoder, not only verification of the authenticity of the document but determination of the treatment to be given to it. <IMAGE>
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