Inovinks’ New IR Pigments – More than a Mirage

Infrared (IR) is part of the electromagnetic spectrum that lies immediately beyond red light and is therefore invisible to the naked eye. Because of this, IR inks are widely used to create covert features that are both highly secure and machine readable.

Over the years, a lot of work has gone into research to try and improve infrared absorbing pigments. Not much has changed from the days when carbon black was the infrared absorbing, machine-readable pigment of choice. In fact, it is still specified in many designs of banknotes and high-security printed products because issuing authorities and designers are simply unaware of the improvements that have been made in this increasingly important area of banknote and document security.

The inefficiencies of older versions of infrared absorbing pigments are numerous. The inherent dark colour of carbon black limits the choice that designers have when choosing the colour of the base ink. Printers and ink makers are sometimes challenged in matching ink colours when infrared absorbing materials are specified. This aspect has been improved recently with the use of lighter colour machine-readable materials, but the amount of material required to be added to security inks can be significant, thereby making the finished infrared absorbing feature much more expensive This also impacts on sustainability goals because so much active material (usually metals) is required. Furthermore, the use of rare earths as an infrared machine-readable security feature should be discouraged because of the social and environmental repercussions of rare earth mining.