Optically variable ink

Optically variable ink (OVI) also called color shifting ink is an anti-<a href="/facts/Counterfeiting/MaYRLckY">counterfeiting</a> measure used on many major modern <a href="/facts/Banknote/mm6H2XI4">banknotes</a>, as well as on other official documents (<a href="/facts/Licensure/Yymanvzo">professional licenses</a>, for example).
The ink displays two distinct colors depending on the angle the bill is viewed at. The <a href="/facts/United_States_fifty-dollar_bill/aA19d0PL">United States fifty-dollar bill</a>, for example, uses color shifting ink for the numeral 50 so that it displays copper at one angle and bright green in another.
OVI is particularly useful as an <a href="/facts/Counterfeit/MaYRLckY">anti-counterfeiting measure</a> as it is not widely available, and it is used on <a href="/facts/Security_printing/DDAvNgrN">security printing</a>. One major manufacturer is a <a href="/facts/Switzerland/LcGuxeTe">Swiss</a> company called <a href="/facts/SICPA/Ukd8flPF">SICPA</a> (Société Industrielle et Commerciale de Produits pour l'Agriculture). Additional suppliers include German company <a href="/facts/E.T._Gleitsmann/ERbx9JfU">Gleitsmann Security Inks</a>, <a href="/facts/Sun_Chemical/ooye9YaM">Sun Chemical</a> (through their Brand Protection Division based in Manchester, UK), and the Swiss company Printcolor AG, located in Berikon, <a href="/facts/Switzerland/LcGuxeTe">Switzerland</a>.
Color-shifting inks reflect various wavelengths in white light differently, depending on the angle of incidence to the surface. An unaided eye will observe this effect as a change of color while the viewing angle is changed. A color copier or scanner can copy a document only at one fixed angle relative to the document's surface. It uses finely powdered <a href="/facts/Pearlescent/ykc1opK8">pearlescent</a> <a href="/facts/Glitter/92J5LqBl">glitter</a>.

Optically variable ink open-in-new

Optically variable ink