SCIENCE PHOTO LIBRARY SCIENCE PHOTO LIBRARY
Banknote security, UV anti-counterfeit marker. Close-up of a UK twenty-pound sterling (20 GBP) banknote under ultraviolet (UV) light, revealing the anti-counterfeiting marker (in the form of the number 20) that is not seen under visible light. The UV light causes chemicals in the marker to fluoresce, making the marker visible as it glows. The colours depend on the chemicals used. UK and Euro banknotes use compounds of the rare earth (lanthanide) elements europium and terbium. For this image in visible light, see image C013/2678.
Model release not required. Property release not required.