Abstract: A film having antistatic properties, said film comprising a transparent polymeric substrate, said substrate being partially opacified on at least one surface so as to provide opacified and non-opacified regions and wherein both the opacified and non-opacified regions are coated on at least one surface with an antistatic coating said coating having greater than 70% transmission. In particular for use as a transparent antistatic coating on polymer banknotes including transparent window regions.

Abstract: An optical security device, including a substrate (102) having a first surface and a second surface; and a metallic nanoparticle ink (104) provided intermittently in at least one area on the first surface (102) to produce a reflective or partially reflective patch or patches; wherein a high refractive index coating (106) is applied over the area or areas (108) in which the metallic nanoparticle ink is provided, the high refractive index coating (106) adhering to the first surface (102) where the metallic nanoparticle ink is not present, thereby retaining the metallic nanoparticle ink (104) between the first surface (102) and the high refractive index coating (106).