Giesecke & Devrient has introduced a security system for currency that can reduce the risk of receiving bogus bills.

The Munich-based technology firm said Tuesday it has introduced MAGnite, a technology that embeds very small capsules in the pigment of ink used to print bank notes. The capsules rotate when they come in contact with a magnetic field, such as the one produced by magnets found in the loudspeakers of mobile phones.

When a user places a bank note printed with MAGnite over a mobile phone or other magnetic device, the note displays an image in the shape of the magnet.

"A bank note is opaque, but the interesting thing is, every magnet has a field," Bernd Kümmerle, head of Giesecke & Devrient's bank note printing division, told American Banker. "All you need is a magnet, which is in your phone. We make the magnetic field visible by just holding a bank note on top of that magnet."

Kümmerle compares the capsules that Giesecke & Devrient embeds in the ink to window shades that, depending on their tilt, either block or pass-through light. In the presence of a magnetic field, the capsules turn and thereby change the appearance of currency printed with them. "If you put a bank note with our feature on [a magnet], our capsules will go into a see-through position," Kümmerle adds.

The technology taps the same micro-encapsulation methods used by scratch and sniff perfume samples, according to Kümmerle.

The company says it has designed the service for use by consumers although it works with any magnet, including those inside theft-protection systems used by retailers.

The bank notes themselves must be printed with the company's display-embedded ink. Kümmerle says central banks can buy bank notes from Giesecke & Devrient — the firm prints currency for roughly 60 countries worldwide — or purchase the ink from Giesecke & Devrient and print the notes themselves.