Valuable document, especially stamps, with a safety element

摘要

The document (3) has an optically identifiable safety element (4) exhibiting a resolution of 300 dots per inch (dpi), where the safety element comprises a coding of information over the document. The safety element has a two dimensional structure, and is designed as a matrix code or a bar code. The structure of the safety element is not identified by a naked eye. The safety element is subsequently imprinted or attached during manufacturing of the stamp. The safety element is used to locate the document on a postal item. Independent claims are also included for the following: (1) a method for testing a valuable document (2) a device for testing a valuable document.