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.