Luminescent Security Properties Of Banknotes

Since the beginning of human civilization, whenever any item has gained some value a fake version has also appeared shortly afterward on the market. This endless combat between the owner of the original product and the counterfeiter still continues to our day. Better and more affordable color copiers have added a new dimension to the forgery. Appearance of the color scanner to the market has also made the task to counterfeit the banknotes a lot easier. There are many methods to render the color copier’s or scanner’s task more difficult or impossible. One of these methods is to utilize luminescent (fluorescent or phosphorecent) pigments that change color under non visible light sources. The main features to utilize the use of the fluorescent phenomenon in banknotes are paper fluorescence (non fluorescence), fluorescent security fibers and fluorescent printing. Inks, fibers and planchettes based on organic fluorescent substances are regularly used to produce security elements. The luminescence of such elements is absent in white light but is revealed under actinic radiation. One method is to combine fluorescent and phosphorescent materials in a security element. To discriminate between fluorescence and short-lived phosphorescence a portable phosphorescence detector can be used. In this study we measured the luminescence radiation spectra of the different kinds of euro banknotes and analyzed the luminescence emission spectra. We also tested the durability of banknote luminescence and analyzed the results. Novel luminescence spectral data will be provided.