1. A method for authenticating and/or identifying a security article comprising: a transparent or translucent substrate, and on a side of a first face of the substrate, a first image, the method comprising the steps of: at least partially superimposing the first image of the article with a second image produced by an electronic imager, and changing an angle at which an observer observes the first and second superimposed images so that an authentication and/or identification information item for the security article is observable.