| 摘要 |
<p>Banknote paper is protected against counterfeiting by using printing inks with a clearly detectable metameric effect. Preferably the inks have a colour distance of at least two Delta-E units, and give the metameric effect on passing from daylight to artificial light and back. At least twoo such inks may be used, with a like sense impression in daylight but different in artificial light, or vice versa. Incandescent light may be used as the artificial light. The printing may include two partial fields which abut with sharp borders and give the metameric effect e.g. as special test fields.</p> |
