A security element (2, 4), for inclusion in or application to a security document such as to be visually recognisable from both sides of the security document, is made up of multiple layers and comprises an interference element (I) with coloration effect and diffraction structures (8). According to the arrangement of the layers and the diffraction structures (8) on a transparent substrate (S), the coloration effect and/or the diffractive optical effects can be seen from one or both sides of the security element (2, 4). The security element is particularly suitable as double-sided window strands (4) and as label or transfer element (2) over a hole (3). |