Indian team makes doubly secure ink to thwart counterfeiting Premium

Indian scientists develop new ink using nanoparticles to enhance security features in banknotes and documents, combating counterfeiting effectively.

Governments and financial institutions take painstaking efforts to consolidate banknotes, cheques, and passports with a variety of security features to protect them from counterfeiting. Yet every so often a counterfeiter emerges who can recreate these features and pass off fake documents as real ones. In response, institutions constantly develop newer and better components that are even harder to falsify.

Now, scientists from India have come up with an ink they say can make counterfeiters’ jobs harder.

Counterfeiting is a serious threat to a range of enterprises. Spurious medicines packaged to look like the real thing can delay proper treatment or even kill. Branded consumer goods these days have tamper-resistant packaging to prevent cheats from selling low-quality replicas.

The printing of items with safeguards against counterfeiting is called security printing. It implements features that humans can detect by themselves or using simple tools. Examples include optically variable ink (whose colour appears to change when viewed from different angles), watermarks, holograms, and security threads. Features like raised shapes and shifting textures are security-printed features a person can check using the sense of touch.

Security printing can also incorporate more complex features that only machines can detect. Some modern passports include a small radio-frequency identification chip that only a scanner can read. Other examples include invisible barcodes, digital watermarks, and holograms.

An important security-printed feature on Indian banknotes is a number panel in fluorescent ink located at the lower left corner. The numbers here are visible only in ultraviolet light.

Scientists from the Institute of Nano Science and Technology (INST), Mohali, and the Bhabha Atomic Research Centre (BARC), Mumbai, have now reported a new ink they have made using nanoparticles. Nanoparticles are objects less than 100 nanometres (nm) wide. Because of their small size, they have properties that don’t appear in larger objects: they interact differently with light, respond differently to magnetic fields, and are chemically more reactive.