GRID IMAGE HAVING ACHROMATIC GRID FIELDS

The invention relates to a grid image having two or more achromatic grid fields (22, 24) including a visual appearance image dependant on the viewing angle, each field containing a grid pattern composed of a plurality of straight dashed grid lines (26) influencing an electromagnetic radiation. According to the invention, the grid fields (22, 24) are arranged in the shape of a predetermined motif (20), - the grid patterns are characterized by the grid pattern parameters of orientation, distance and profiling of the grid lines (26), - in the grid fields (22, 24) at least one of the grid pattern parameters of orientation, distance and profiling varies randomly with a predetermined distribution across the surface of the grid field such that the grid fields (22, 24) are characterized by the grid field parameters of median orientation, orientation variance, median distance, distance variance, profiling and profiling variance of the gridlines (26), and- within the predetermined motif (20) at least the grid field parameter of median orientation from grid field (22, 24) to grid field (22, 24) discretely changes.