Multi-tonal copy evident document methods and products
US8355179B2 · kind B2 · utility
Inventor
Key dates
| Filing date | Mar 31, 2009 |
| Grant date | Jan 15, 2013 |
| Priority date | — |
| Expiry date | Jul 11, 2031 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G2215/00932
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present disclosure relates to a printed multi-tonal document with enhanced copy evident distortions security features and a method of printing such document. The document may include a multi-tonal background screen image area including a first set of halftone elements and a multi-tonal foreground hidden warning text and/or graphic screen image area including a second set of halftone elements, wherein the first set of halftone elements may be smaller in size than the second set of halftone elements. The multi-tonal foreground hidden warning text and/or graphic image area, when electronically copied, may appear different from the background of the copy of the document.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.