Optically variable ink

OVI (English: Optically Variable Ink = optically variable color) is a technique to increase the security of banknotes and documents. This is a special color that takes on a different hue depending on the angle. Usually, OVI inks are transferred to the substrate by screen printing.

Technology

Basic component is a colorless substance, permeated by microscopic and multilayer flakes (pigments ). These flakes provide the viewing angle-dependent color change to brown as green or green to purple. To this end, the pigments must be aligned in a preferred direction during printing.

Security

Because of this color printed with OVI technology shares the originals for color copies or scanned photographs appear colored. However, the POI technique alone saw for professional counterfeiters represents a not sufficiently high hurdle Therefore, this security feature is combined with Euro bank notes with other techniques such as the watermark, optically variable features (holograms, kinegrams ), the security thread and other security features.

Advantage of this technique are the moderate cost and the relative ease of integration in the protected notes and documents.

Application

Like most bills, also euro banknotes (50, 100, 200 and 500 euros) a POI item. The lower right number on the back ( pictures of the bridge ), which indicates the denomination is printed with the POI technique.

In addition, the POI technique is also used in the electronic identity card, passports, visas, smart cards and packaging.