Covert Security Features

Source: Giesecke & Devrient
Covert security elements provide another authentication method. These are integrated into inks, threads, and foils and thereby extend the functionality of these elements to further verification levels. Some elements have been specially developed for checking using small handheld devices at bank counters and points of sale. Other elements are suitable for checking by machines in commercial and central banks.
Hidden Codes
Hidden codes created with laser on the printed banknote. These are invisible to the human eye and can only be read under an infrared light.
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Machine-readable magnetism
Banknote printing companies offer innovative magnetic coding systems for security threads, from simple yes/no recognition through to complex coding (MultiCode). The appropriate reading systems have been developed for checking using a sensor.
Machine-readable electrical conductivity
Electrical conductivity along the entire length of a security thread is a simple machine-readable element that can be integrated in most types of thread.
Machine-readable infrared characteristics
The infrared characteristics of banknotes (IR-absorbing and IR-transparent inks) can be checked by sensors in machines at commercial and central banks.
UV fluorescence – authentication using a UV lamp
Hybrid_unbedruckt_UV_Licht_Web_DSC_4336_IMAGE_1COL Different colors, color combinations, or rainbow effects become visible when viewed under UV light.
Phosphorescent inks on banknotes can be checked by sensors in processing machines.
Pole – authentication using a polarization filter
Pole is an innovative and attractive security element that is suitable as a replacement for and/or addition to the frequently used UV fluorescence. In 2008, the Pole security element received an award for “Best New Currency Feature” from the International Association of Currency Affairs (IACA)