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Showing papers on "Watermark published in 1977"


Patent
23 Jun 1977
TL;DR: In this paper, the method of making the document comprising preprinting a "VOID" or other warning or cancellation phrase pattern in half tone or multitone on the document and camouflaging this pattern is also disclosed The document bears a watermark which adds to the security of the system
Abstract: Disclosed is a protected document such as a negotiable instrument, a title instrument, identification document or other documents which should be kept secure from illegal copying by color copiers The method of making the document comprising preprinting a "VOID" or other warning or cancellation phrase pattern in half tone or multitone on the document and camouflaging this pattern is also disclosed The document bears a watermark which adds to the security of the system

87 citations