Optically Variable Ink
Encyclopedia
Optically variable ink (OVI) is an anti-counterfeiting measure used on many major modern banknote
s.
The ink displays two distinct colors depending on the angle the bill is viewed at. The United States fifty-dollar bill
, 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 anti-counterfeiting measure as it is not widely available; the major manufacturer is a Swiss company called SICPA.
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.
Banknote
A banknote is a kind of negotiable instrument, a promissory note made by a bank payable to the bearer on demand, used as money, and in many jurisdictions is legal tender. In addition to coins, banknotes make up the cash or bearer forms of all modern fiat money...
s.
The ink displays two distinct colors depending on the angle the bill is viewed at. The United States fifty-dollar bill
United States fifty-dollar bill
The United States fifty-dollar bill is a denomination of United States currency. Ulysses S. Grant is currently featured on the obverse, while the U.S. Capitol is featured on the reverse. All current-issue $50 bills are Federal Reserve Notes....
, 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 anti-counterfeiting measure as it is not widely available; the major manufacturer is a Swiss company called SICPA.
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.