| 摘要 |
A security document is provided comprising a substrate having a top surface for carrying indicia. The top surface has a plurality of areas. Each of the areas contains background printed matter on the top surface. The background printed matter made up of a pattern of background elements. Each of the areas also contains a security term printed on the top surface of the substrate. The security term is composed of a pattern of security term elements. The background elements and/or the security term elements differ in element size, shape, angle, density, and/or frequency between adjacent areas. Also, within each of the areas either the background elements or the security term elements are not readily duplicated by a color copier while the remaining elements in the area are readily duplicated by a color copier. This results in a visually perceptible security term being produced upon copying of the security document. |
