光学检验技术在假币鉴别中的应用

Distinguishing Counterfeit RMB Currency with Optics

制售假币案件中,收缴的假币是最重要的物证,是案件关联串并、源头追溯的关键依据。本研究以45张不同冠字号码机制假人民币为研究对象,采用显微镜、文检仪在不同光源下对其印刷图文特征、纸张及油墨材质特征、后期加工凹凸特征等进行放大、侧光、透光、光致发光、吸收反射等光学检验。根据版面固有图文特征的差异将45张票样分为10个版型;根据油墨、纸张等材质检验结果确认其中的14张票样来自6个印刷窝点;通过后加工特征检验确认2张票样来自同一后加工窝点,为案件关联串并、源头追溯提供了依据。所有判定为相同窝点印刷的结论破案后得到了印证。

Counterfeit currencies,seized from cases of manufacturing and/or selling them,are the most importantevidential materials as they are key to link and/or trace the involved cases.The subjects here were 45 fake 100-denominationRMB notes that were printed of different serial numbers and fabricated through offset pressing.With microscope and videospectral comparator being used under various lights,the optical detection was carried out into the items of magnifi cation,sidelighting,transmission,photoluminescence and infrared absorption-and-reflection to highlight the fake notes’specifics aboutprinted patterns,paper,ink and post-processed reliefs.Based on the graphic features,all the 45 fake notes were divided into 10types,having made 14 ones determined to be printed in six different locations according to their printing inks and used paper,plus the other 2 ones confirmed from same one den by their post-processing features.Thus,a piece of evidence was providedfor cases’linking and source tracing.The judgment of printing from same den was proved correct with the solved cases.