| 摘要 |
The invention relates to improvements in security documents, and a method for making such security documents. The security document made from a fibrous security substrate comprising at least one watermark and a background wiremark pattern. At least one of the said watermark or watermarks comprises at least one machine detectable pattern and, the at least one machine detectable pattern comprises a series of regularly repeating elements in which the pitch of the elements of the pattern is selected to be different from that of the background wiremark pattern formed in the substrate and lies in the range of (5) to (100) elements per cm. |
