Method for document marking and recognition

摘要

Disclosed is a process which comprises (a) applying to a recording sheet a marking material comprising a Raman-detectable component which, when irradiated with monochromatic radiation, exhibits a detectable Raman spectrum, thereby forming a mark on the recording sheet; (b) irradiating the mark on the recording sheet with monochromatic radiation; and (c) measuring the Raman spectrum of radiation scattered from the mark when the mark is irradiated with monochromatic radiation.