Abstract: The invention relates to a security feature (8) for security documents (9), in particular bank notes. A first body colour (51) is applied in a first region (1) and a printing ink (53), in particular a day luminescent dye, is applied in an illuminating region (3). The printing ink (53) is applied outside the copy dye range of the four colour prints according to the Europe-scale or DIN-scale. According to the invention, a first mixed colour (54) of the first body colour (51) and the printing ink (53) is applied in a first overlapping region (13), and the first mixed colour (54) is arranged outside the copy dye range or in the edge region of the copy dye range, in order to increase protection against forgery.

Abstract: A security document, such as a banknote, includes an optical security area having a first periodic optical structure and a security sign provided on the security area and configured to circumscribe a second periodic optical structure which is disposed in offset relationship to the first periodic optical structure. Arranged on the security area is a see-through element for enhancing recognizability of the security sign on the security area. The see-through element defines hereby a viewing zone which covers part of the security sign so as to render this part of the security sign visible by the naked eye.

Abstract: A security document, such as a banknote, includes an optical security area having a first periodic optical structure and a security sign provided on the security area and configured to circumscribe a second periodic optical structure which is disposed in offset relationship to the first periodic optical structure. Arranged on the security area is a see-through element for enhancing recognizability of the security sign on the security area. The see-through element defines hereby a viewing zone which covers part of the security sign so as to render this part of the security sign visible by the naked eye.