Optically variable inks are also called optically variable inks and chameleons. The printed color blocks present a pair of colors, such as: red-green, green-blue, gold-silver, etc. When looking at the front or the side under white light, with the change of the viewing angle of the human eye, it presents two different colors, with strong light variation characteristics, large chromatic aberration changes, and obvious features, which can be identified without any equipment and equipment, and its color angle effect cannot It is reproduced with any high-definition scanner, color copier and other equipment. The printing characteristics cannot be imitated by any other ink and printing method. The anti-counterfeiting reliability is extremely strong, so it is designated by many countries in the world for the most stringent and difficult requirements. For the anti-counterfeiting of the largest currency and negotiable securities, some well-known manufacturers in China have also used it for packaging anti-counterfeiting.