Currently, counterfeiting of these documents is possible using sophisticated color copiers. In contrast, the invention produces copy-proof instruments that are both indistinguishable from genuine items produced with previous technology and that result in obviously bogus copies when fraudulent duplication is attempted. The invention forms lines into various patterns in a manner imitative of intaglio or gravure printing. The pitch of the lineations is deliberately selected to vary minutely from the pitch of the scanning trace of various copying machines such as photocopiers, video opticons, and others. The variation in pitch can be obtained by deliberately manufacturing the document with the desired pitch or, after placing the image on the document, changing the dimensions or geometry of the document to effectively skew the pitch parameter. Figures