1. A method for authenticating and/or identifying a security article comprising a first image, the method comprising: displaying on an electronic imager a second image produced by the electronic imager or projecting on a background or on the security article a second image produced by an electronic imager, the electronic imager being an electronic device that is independent from the security article, at least partially superimposing the first image of the security article with the second image, and performing a relative motion between the superimposed first and second images so as to make it possible to observe an authentication and/or identification information item for the security article during the relative motion between the superimposed first and second images, and an effect of motion or of animation being observed during the relative motion between the superimposed first and second images.