closeup of euro under uv lightIt is fascinating to consider just how many high-tech security features are hidden in the banknotes that pass through our hands and travel in our pockets every day. These security features are aimed at making banknotes highly difficult to counterfeit, and many of them are so intricate in detail that often go unnoticed.

So just what are these newer security features that are becoming a part of national currencies all over the world? In last week’s post, we covered 4 major security features in currency: specialized material, the watermark, the clear window, and microprinting. Here are 4 more high-tech security features found in today’s currency.

Security thread

Perhaps the most commonly seen security thread in currency is the MOTION® technology manufactured by Crane & Co., the very same manufacturer of cotton-based paper products for many national currencies. This technology features hundreds of thousands of tiny micro-lenses interacting with graphics and first appeared in Sweden’s 1000 kronor banknote. Crane’s MOTION technology is now a part of 16 national currencies in over 45 denominations, including the Thai baht, the U.S. dollar, the Lebanon pound, the Korean won, the Chilean peso, and the Hong Kong dollar. Security threads can appear invisible on a banknote, feature prominently on the note’s face, or even be woven in and out; but no matter how one is utilized, a security thread will appear as a solid line when held up to light.

Ultraviolet feature

Many banknotes—likely more than you think—even appear differently under different forms of light, with special imagery being printed in inks that only a UV light can detect. On the English 50-pound note, for example, the number 50 appears in bright red and green when held under a UV light. Other currencies that make use of this technology in some form include the Hong Kong dollar, the euro, the Singapore dollar, the Peruvian neuvo sol, the Thai baht, and the Iraqi dinar. U.S. banknotes feature UV strips that will glow under UV light.

Raised ink

Also called intaglio printing, this is a feature that can be detected by touch. Raised ink is often a detail featured on the banknote’s inscribed value and along other small image elements on the face of the note. The Chinese yuan features raised ink in the note’s value; the Indian rupee has raised printing to the left of the notes’ watermarks; and the Japanese yen features a portrait, letters, and identification marks all printed in raised ink. Many other national currencies make use of this technology as well. Intaglio printing can also be used to help the visually impaired identify different denominations of banknotes.

Color-shifting ink

Another feat that can be achieved with special printing is the ability to have a portion of a banknote appear as different colors depending on which angle it is viewed at. This is made possible with optically variable ink, which reflects various wavelengths of light differently. Some U.S. banknotes feature color-shifting ink in the numerals located at the lower right corners, with the ink appearing green when viewed directly and black when the note is tilted at an angle. Other major national currencies that make use of variable ink include the Korean won, the Bangladesh taka, the Russian ruble, the Indian rupee, and the euro.