Security document with positive authentication gradient image and negative authentication gradient image

摘要

The invention relates to a security document (1) comprising an image layer (2) having an identification image (4) in a first image area (3). The security document comprises, in a second image area (5), a first authentication image (7), which is a positive version of the first image (4), and a negative version of the first identification image (4). An authentication image (6) composed of a certain second authentication image (8). The authentication images (7, 8) can be viewed at different angles to form a tilted image. Intercomparison of positive and negative tilt images and comparison with identification images allows for improved tampering detection. [Selection diagram] Fig. 1