Showing papers on "Watermark published in 1987"

Document bearing characteristic ink-printed indicia juxtaposed with corresponding characteristic synthetic watermark and method for producing same

Abstract: A document security system is provided by providing each document with a synthetic watermark, for instance using the process, compositions and apparatus disclosed in the aforementioned U.S. patent of Norris, et al and, within the perimeter of at least one of the symbols which is provided by the synthetic watermark, an identical complementary or otherwise corresponding symbol is printed using ink, paint, dye, stain or similarly contrastingly pigmented substance so as to create, in combination with the synthetic watermark a juxtaposition that can be looked-for as evidence that the document is genuine and its serial number unaltered.

Method of making a tool for stamping round shaped watermark screens used to make filigranes and apparatus therefor

Abstract: 1. Method for the production of a steel tool serving for the stamping of a forming wire of a mould used in the fiduciary paper industry for producing watermarks, said tool being obtained by electro-erosion from an electrode, comprising the following successive stages : a) the values of a black and white image are digitized (2) in pixels with several shades of grey, b) an electrode is engraved automatically by machining (6), plane by plane, directly from the preceding data, with an engraving depth increasing uniformly with respect to the initial surface of said electrode, the engraving depth being in biunivocal correspondence with the shades of grey, c) the electrode thus engraved is disposed (7) in a bench for machining by electro-erosion until a tool (8) having the desired surface state is obtained.

Paper for developing watermark

Abstract: PURPOSE:To obtain the title paper resistant to yellowing and blotting, capable of developing a watermark by printing at a small lot and low cost and useful for preventing the forgery of merchandise bond, securities, etc, by adding a fluorescent brightener for paper-making use to a printing paper or a coating layer of a paper CONSTITUTION:A fluorescent brightener is added to a paper for watermark printing or to a coating layer of a paper to obtain the objective paper having stable quality When the paper is printed with a clear ink, the ink is impregnated into the paper or the coating layer to develop a watermark while keeping the surface of the paper or the coating layer from covering or masking Light transmits through the transparent ink even if a part of the component constituting the transparent ink is colored to yellow color and, accordingly, the yellow visual appearance is eliminated to give a white paper