手印物质转移技术鉴别文书上伪造红印油指印

Fingerprint Substance Transferring for Identifi cation of Red-inkdisplayed Fake Fingerprints on Documents

研究文书上伪造红印油指印的鉴别方法。首先,利用光敏指纹印章制作不同遗留时间的伪造红印油指印,手指直接捺印不同遗留时间的真实红印油指印。其次,利用转移介质完成真伪红印油指印的印迹物质转移,并对介质进行手印显现(茚三酮显现方法)处理,具体分为两种模式,模式一:在物质转移过程中,使红印油指印的印迹物质与转移介质上的手印显现工作液物质发生显现反应,即物质转移与显现反应同时进行;模式二:先将红印油指印中的印迹物质通过转移工作液转移至介质上,再对介质上的印迹物质进行显现处理,即先进行物质转移,后完成显现反应。最后,观察显现处理前后的转移介质上指印变化情况(有无赫鲁曼紫物质生成)。结果表明:1)模式一与模式二均成功实现红印油真伪指印物质转移及显现反应,介质上真实红印油指印位置处有赫鲁曼紫物质生成,而伪造指印无赫鲁曼紫物质生成;2)模式二的显现处理效果更优于模式一;3)采用模式二成功实现遗留时间分别为1、2、7、15、30 d的红印油指印物质转移,且转移介质经茚三酮显现处理,介质上真实红印油指印位置处均有赫鲁曼紫物质生成,伪造指印均无赫鲁曼紫物质生成。本文成功验证了真伪红印油指印的物质成分的分布存在差异;提出了一种基于物质转移原理鉴别真实和伪造红印油指印的方法,并通过实验得到有效验证;利用该方法成功实现文书上遗留时间分别为1、2、7、15、30 d的真伪红印油指印的有效鉴别。

Fingerprint seals or fi lms,made from people’s real fi ngerprints,are at times used for related individuals to do their business conveniently,yet leaving behind the risk for violators to forge these fi ngerprints to seek illegal interests.At present,the fi ngerprint identifi cation mainly focuses on two aspects:one is the traditional morphological comparison;the other is the emerging deep-learning recognition.Unfortunately,there is still a lack of scientifi c,effective,mature and stable examination methods to distinguish the genuine fi ngerprints from those fake ones which are often appeared with their redink-displayed versions on documents.In principle,genuine fingerprints definitely contain the substances transferred from their human donors,yet the fake fi ngerprints only contain substances from the used ink.Therefore,an identifi cation method was here designed to discern the genuine and fake fingerprints displayed with red ink on documents,and verified of its scientifi city and effectiveness through experiments.Specifi cally,the fake fi ngerprints were made via photosensitive fi ngerprint seals imbibing red ink and then pressing against the paper carriers,with the genuine fi ngerprints being prepared by relevant fi ngers directly pressing against red inkpad and then imprinting onto paper carriers.Both the genuine and fake fi ngerprints were placed for designated durations of time.The transfer medium was used to convey the red fi ngerprints(both geunine and fake),and treated with ninhydrin operation under two modes:one,developing the fi ngerprints through reaction of fi ngerprintharbored substances(if present)with the fi ngerprint developer along with the transferring process;the other,fi rst having the fi ngerprints transferred onto the medium previously soaked with related working fl uids and then developed via fi ngerprint developer.Consequently,the transferred fi ngerprints were observed of their changes before and after displaying treatment(whether the Ruhemann’s purple appeared on the transfer medium).The results showed that:1)two modes were both able to successfully transfer the fi ngerprint substances and develop the fi ngerprint on the transfer medium,demonstrating that genuine fi ngerprint did result in the Ruhemann’s purple appearing while none with the fake fi ngerprint;2)the mode two displayed better processing effect than the mode one;3)the mode two successfully transferred the fi ngerprints left for 1,2,7,15 and 30days,and had Ruhemann’s purple emerged when ninhydrin treated to the relevant medium transferred from genuine fi ngerprint while none from the fake fi ngerprints.Evidently,there are differences in the distribution of componential substances between genuine and fake fi ngerprints.A method has been herewith established to identify genuine and fake fi ngerprints on documents based on the principle of fi ngerprint substance transferring,verifying that the identifi cation can be realized with the fi ngerprints retained for legacy time of 1,2,7,15 and 30 days.