Agile Methodology for Identifying Original and Fake Printed Documents based on Secret Raster Formation

A method of identification of original and fake prints has been developed. Security elements are printed using an offset printing method, which we will call original printing. In parallel, we will print bitmap security elements on copiers. We will call this process fake printing. Such types of rasterisation were developed to make the difference between an original print and a fake print visible to the naked eye. A method of detecting fake printing has also been developed by measuring the change in the percentage of raster dot, dot gain, trapping, optical density, ∆lab, and change in tonality. The protection of the printed document is created when the image is transformed by amplitude-modulated rasterisation based on the mathematical apparatus of Ateb-functions. During rasterisation, we create thin graphic elements that have different shapes and are calculated according to developed methods. The size of a single dot of a raster element depends on the selection of the rasterisation method and the tonal gradation value of each corresponding pixel in the image. During rasterisation, a raster structure is formed, in which the value of each raster element is related by the value of the Ateb-function with tonal gradation, as well as a change in the angle, lines and shapes of the curves of a single raster. We offer raster image printing on various paper samples that are widely used today.