DOCUMENT, METHOD AND DEVICE FOR PRODUCING A DOCUMENT AND METHOD AND DEVICE FOR IDENTIFYING A DOCUMENT

摘要

A planar sheet comprising, on a first surface of the sheet, at least one printed mark, and on a second surface of the sheet, opposite the first surface, at least one invisible printed mark vertically adjacent to the mark printed on the first surface. In at least one pair of vertically adjacent marks formed on the opposite surfaces, at least one of the marks of the pair has unique content. At least one invisible mark can be a two-dimensional barcode and/or at least one invisible mark can be a copy-protection mark. The content of at least one mark can be representative of the position of an invisible mark on the sheet.