Special-effect inks

Source: Giesecke & Devrient
iriodin_01_IMAGE_1COLPrinting using optically variable special-effect inks produces intriguing security elements that are quickly and easily identifiable and create irreproducible effects. The special-effect inks change their appearance depending on the angle from which they are viewed: they are visible or invisible, or they change color.Banknote printing companies offer a range of sophisticated designs, all of which are screen printed: from iridescent to optically variable colors. Because all effects can be printed on the banknote in perfect register both horizontally and vertically, they can be ideally integrated into any design. Special-effect inks are available in various colors and can be applied to the banknote as a localized patch, as stripes, or as a combination of the two.
Interactive printing effects
magnite__IMAGE_1COLMAGnite is an interactive security feature for banknotes based on verification that is actively triggered by the user with unusual optical effects. The feature uses high-performance pigments that allow reversible changes between two color states. Highly resistant micro capsules enclose these pigments, without in any way limiting their flexibility. The alignment of the pigments and the colors perceived can be controlled externally simply with magnetic effects.
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This produces dynamic and contrasting effects, induced with magnets that are commonly available. Any individual can verify the authenticity of banknotes, for instance using the speaker magnets in their cell phone. There are therefore article surveillance systems available at the point-of-sale, among other things.
Iridescent print effects
iridescent_v2_02_IMAGE_1COLIridescent print effects are based on special luminescent inks that change color when the banknote is tilted so that the printed image becomes visible or invisible. The visibility or invisibility of the printed image depends on the incident angle of the light falling on the banknote. Iridescent effects are optically variable and therefore difficult to copy. These characteristics make them popular for increasing the level of security in existing banknote designs.The iridescence owes its striking effect to tiny shimmering plates made from mica, which are mixed with a transparent varnish. When this varnish is applied to a substrate in the screen printing process, these tiny plates line up and can be seen as an iridescent effect.Iridescent effects are available in a broad color spectrum. As they can be printed onto the note design horizontally and vertically in register, they can be perfectly integrated into an existing print design. They are available as a patch, stripe, or a combination of the two. If the iridescent special-effect ink also contains additional UV pigments so that it appears different in daylight and UV lights, this represents yet another obstacle to the counterfeiter.
Optically Variable Ink
STEP (Shimmery Twin Effect Protection) is an optically variable ink based on liquid crystal pigments. When viewed from different angles, elements printed with this ink appear to change color (the “color-shift effect”, e.g. from green to blue).
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Security at your fingerprints
FEEL (Fast Energy Effective Link) is an interactive security feature for banknotes. The warmth of your fingertip is enough to alter the color at a specific location on the banknote. This makes it very easy to authenticate.The secret is thermochromism, the special ability of materials to change color depending on the ambient temperature.FEEL undergoes a clearly visible color change as soon as it is exposed to heat. Depending on the design, multiple layers of motifs and information printed over each other may become visible. The heat generated by the skin or by lightly rubbing with the fingertip is sufficient to verify authenticity.
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 FEEL in its normal state  FEEL in action