PRINTS INVOLVING CONCEALED INFORMATION AND METHOD OF IDENTIFYING CONCEALED INFORMATION

摘要

PPROBLEM TO BE SOLVED: To provide a means for effectively utilizing a concealed information in the form of wave frequencies at a peak level of an infrared absorption spectrum of a resin that constitutes a printing ink. PSOLUTION: The prints whose basic material (1) is printed with the words E (3) in an ink that contains an alkyd resin and the words X (4) in an ink that contains an acrylate resin, respectively, whereas the words in the above prints are expressed as an image after mapping measurement by microscopic direct reflection, one of the infrared analytic methods, on the respective specific absorption peaks of resin strengths in an infrared absorption spectrum of direct reflection on a section printed with the words E (3) and the words X (4). Since the images obtainable as above are specific and different, respectively, such characteristics are utilized as a means for avoiding forgery or concealment of an information. The forgery prevention can be more effective when not less than 2 resins with different peak levels and strengths are combined. PCOPYRIGHT: (C)2004,JPO