Patent US 4,222,662

A photo I.D. card having the photograph, and/or signature, and/or coded indicia of an authorized holder which is visible under ordinary room illumination also carries a second photograph of the user. The second photograph is in the form of a transparency which is sandwiched between a piece of retroreflective material and an optical filter which is opaque to light of normal intensity and wavelength but which is transparent to infra-red or ultra-violet radiation. Also disclosed is apparatus for reading both the visible and invisible photographs, signature, and data on the card by means of a CCTV system. Any attempt to alter or forge the I.D. card can, thus, be readily detected.