Patent ID: 8230786

Claim:
A method of engraving a plate for intaglio printing of sheets carrying a pattern of rows and columns of security papers, comprising the steps of generating on a computer at least one original depth-map consisting of a three-dimensional raster image of at least a part of one of said security papers; generating a master depth-map of the plate to be engraved, which master depth-map consists of three-dimensional pixel data and provides for multiple repetitions on the plate of said at least one original depth-map according to a pattern of rows and columns corresponding to the security papers to be printed on said sheets of security papers, wherein said master depth-map is generated by taking into account information necessary for compensating for sheet distortion created during the intaglio printing process; and controlling a computer-controlled engraving tool to engrave the plate according to the three-dimensional pixel data of said master depth-map, whereby the plate is engraved pixel by pixel by performing a plurality of elementary three-dimensional engraving steps each corresponding to a pixel of said three-dimensional pixel data.