What is optical ink that is used on banknotes?

With modern technology, when you hold a banknote in your hand, you will feel a lot of anti-counterfeiting technology applied to that banknote, especially large denomination banknotes. Among them, Optically Variable Magnetic Ink (SPARK, OVMI) is a modern technology that many countries have used on their currencies.

Optically variable magnetic ink (OVMI), also called SPARK, has visual effects that are based on the magnetic properties of the ink. When the document is tilted, movement of a bright light stripe occurs and the color changes. It is usually applied by screen printing. This type of ink is used for the Euro, Brazilian real, and Russian ruble banknotes and other countries in the world.

A multi-level (visual and machine-readable) security feature. The visual effects are based on the magnetic properties of an optically variable magnetic ink. The ink contains a special magnetic pigment located with the help of magnetic fields within the ink layer. When the banknote is tilted, there is a combination of the color changing effect and (unlike optically variable ink) the dynamic effect of the ink movement (bright parts of the image “change” places). Usually printed by screen printing.