Security patterns for security papers

摘要

The background (10) of a valued paper such as a banknote is divided into two regions with straight and curved lines. The two regions have different colour densities and the region of lower colour density forms a motif. The motif (20) is also overprinted over the lower density region forming the motif on the background. The overprinting is made in a colour chosen to compensate the lower colour density of the background motif so that the latter is invisible to the naked eye but may be seen very clearly on a photocopy including those taken using the most recent photocopier designs.