| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a duplication preventing medium which has an effect for preventing forgery by a color copying machine and a method for making the medium. SOLUTION: A latent pattern such as an alarm mark is formed on a duplication preventing medium by two or more kinds of light reflection parts A, B, C... which are different in reflectance, and the latent pattern is made evident by a duplicate by a color copying machine. In a method for making the latent pattern, backing layers 12-1, 12-2, 12-3... which are different in surface roughness are formed on a backing 11 according to the latent pattern, and a thin metal film layer 13 is formed on it by the deposition of metal.</p> |
