| 摘要 |
A document protected against unauthorised reproduction using copying equipment is described which consists of a paper substrate, a warning marking which is printed with fine constituent elements on a surface of the substrate and a surrounding background which is printed on the surface of the substrate in the same plane as the warning marking, also with fine constituent elements but in a different configuration. According to the invention, the constituent elements of both the warning marking and the background have the same colour and the same density and a decorative design is printed over the warning marking and the background in a paler colour with transparent ink which cannot be reproduced by copiers, in such a manner that the warning marking can be seen with the naked eye. |
