凹版印刷是当代钞票印制的主要防伪手段之一。这种印刷方法起源于中世纪的欧洲。中世纪的欧洲,骑士阶层十分活跃,他们头戴钢盔、身披铠甲,手持剑矛等各种武器,四处游荡。这些骑士对盔甲武器的装饰十分苛求,于是工匠们就在这些钢铁制品上雕刻了各种各样的花纹,这些花饰一般是由工匠直接用凿子雕刻的,也有的是使用酸等药品腐蚀而成的。为了向顾客兜售自己的产品,他们想方设法散发各种商品样本。有的工艺师在自己雕刻的铠甲上抹上蜡烛黑烟子,然后用布擦净铠甲,只留下刻缝中的油烟,把纸放在铠甲上施加 Gravure printing is one of the main security measures of contemporary banknote printing. This method of printing originated in medieval Europe. Medieval Europe, the knight class is very active, they wear a helmet, wearing armor, holding spear and other weapons, wandering around. These knights are very demanding on the decoration of armor weapons, so the craftsmen carved all kinds of patterns on these steel products. These floral ornaments are usually carved by artisans directly using chisels, and others are etched using acids and other chemicals . In order to sell their products to customers, they find ways to distribute a variety of product samples. Some craftsmen carved in their own armor cast candle black smoke, and then wipe the armor with a cloth, leaving only the suture in the fumes, the paper on the armor applied