In papermaking process will alternate red and blue fibers or color patch (dot) mixed into pulp, paper asensitive went before the paper surface, there are fluorescent ultraviolet irradiation.

• 在造纸过程中将红蓝纤维或彩色小片（点）掺入纸浆内，或在纸张未定型前撒在纸张表面，在紫外线照射下有荧光反射。