Spotting forged passports is never easy, but De La Rue,
the British-based company that prints bank notes,
thinks it has a way to make the task simpler. Modern passports contain a
metal strip or hologram woven into the paper which makes them almost impossible to copy.
To get around this, forgers steal genuine documents, wash away the print and
then type in the new details. In its patent (GB 2 345 264), De La Rue has
embedded in the document a strip of aluminium-coated polyester bonded to a dye.
If someone wets the document, the bonding disintegrates, releasing the dye…
