Forgers now find it easy to alter the mugshots on ID cards and passports, says 3M of Saint Paul in Minnesota (WO 02/089072). Because the reverse side of the image is normally opaque, the backing on a phoney image will conceal any damage done to a card by removing the original picture.
3M’s solution is to print the image in reverse on transparent holographic foil and then bond it, image side down, onto a bed of tiny glass beads. The image shows through, illuminated by light reflected by the beads beneath.
If the foil is removed it will take…
