Against falsification made by scratching or erasing, it is necessary to use erasable and reactive inks.

ERASABLE INKS

Those inks can be printed by wet offfset with conventionnel drying.

The adhesion of those inks on the paper is designed for being sufficiently weak in order that when a falsificator tries to scratch off or to erase the printed documents, the erasable ink will disappear before the hand-wrting, and this will reveal the falsification.

REACTIVE INKS

Also called sensible inks to solvents, those inks react to solvents, alcohol, sulfuric esthers, gasoline, pen-erasers, by either a change of colour or a discoloration.

Those inks can show two different reactions:

Either the use of a solvent will discolore the ink and the original colour will be modified, or we can hide an other pigment in this ink, (especially in the dark shades) with for example a dark blue ink which will react in red if the document is in contact with solvents.

In order to increase the security level of those inks, we can add fluorescence under 365nm and 254nm.

Almost all Pantone shades are available.

Recently we have developped reactive inks which can be printed by wet offset with UV drying.