Multi-functional transparent secure marks

摘要

A cellulosic sheet suitable for use as a security document is provided including a multi-functional transparent secure mark formed therein. In accordance with one embodiment of the present invention the secure mark comprises a transparentized portion of the substrate. The cellulosic substrate defines first and second major faces. The transparentized portion comprises a transparentizing composition applied to the cellulosic substrate in a predetermined pattern so as to define a graphical image having a relative transparency selected so as to define an area of increased transparency in the substrate. The transparentizing composition comprises a transparentizing agent and a security agent. In one embodiment of the present invention, the transparentized portion includes a printed portion and printed matter defining the printed portion is covered by the transparentizing composition.