In a method for providing papers of value with authenticity features, a homogeneous mixture is produced in a defined concentration from a feature substance present in powder form and a gas. This mixture is ejected at high speed from at least one nozzle disposed at a given distance from the paper web...http://www.google.de/patents/US5897746?utm_source=gb-gplus-sharePatent US5897746 - Method for equipping papers of value with authenticity features
