| 摘要 |
The application discloses identification and security documents and methods and systems for authenticating such identification and security documents. In one implementation, a document includes a first surface; and a second surface. The first surface comprises a first set of print structures and a second set of print structures. The first set of print structures and the second set of print structures cooperate to obscure the location on the first surface of the second set of print structures. The second set of print structures is arranged on the first surface so as to provide a reflection pattern. In one example, the reflection pattern includes a diffraction grating. The second set of print structures is preferably provided on the first surface with metallic ink. Of course, other claims and combinations are provided too.
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