The fake-guarding material is used for trade mark and packing of famous goods as well as important certificates and bills. It is made of some optical chameleon compound and high polymer. Under visible light it has the same color as the background, and when irradiated with ultraviolet light, it changes its colour thus showing specific mark. The fake produced through duplication and photograph has no this reversible color change. Therefore, the said fake-guarding material is helpful in distinguishing the true and the false. |