Centre for Forensic Science, Department of Pure and Applied Chemistry, University of Strathclyde, 204 George Street, Glasgow G1 1XW, United Kingdom.
Centre for Forensic Science, Department of Pure and Applied Chemistry, University of Strathclyde, 204 George Street, Glasgow G1 1XW, United Kingdom.
Forensic Sci Int. 2023 Aug;349:111758. doi: 10.1016/j.forsciint.2023.111758. Epub 2023 Jun 7.
The aim of this study was to apply the two most effective enhancement sequences for latent fingermarks on Clydesdale Bank and Royal Bank of Scotland polymer banknotes (£10 and £5), as determined in a previous study, to a pseudo-operational trial. The two enhancement sequences established as being the most effective for these types of notes were superglue fuming using PolycyanoUV followed by black magnetic powder, and black powder suspension. Both enhancement sequences included a fluorescence examination before enhancement, and after-treatment using white light, followed by Infrared light. The study conducted by Joannidis et al. was carried out in a controlled laboratory environment where all variables, i.e., the position and age of each fingermark, were known and controlled. However, these conditions do not accurately mirror those of polymer notes seized as part of a criminal investigation. The two most effective enhancement sequences were therefore tested in a pseudo-operational trial to determine whether they would be as effective when applied to banknotes that mimicked those seized in an investigation. To mimic these conditions 102 banknotes from each bank (each containing a mixture of circulated and uncirculated banknotes) were left out in the laboratory for four weeks for the laboratory staff to randomly handle. The results from this pseudo operational trial confirmed the outcomes of the previous study. Superglue fuming (using PolyCyano UV) followed by black magnetic powder was found to be effective in enhancing fingermarks on both Clydesdale Bank and Royal Bank of Scotland polymer banknotes (£10 and £5). This was closely followed in effectiveness by powder suspension which, although it gave slightly poorer results than superglue followed by black magnetic powder, was also effective at enhancing ridge detail. This study also confirmed that Infrared light (730-800 nm), with the addition of an 815 nm filter for notes processed using superglue and black magnetic powder,aided in the reduction of background pattern interference when photographing any ridge detail.
本研究旨在将先前研究中确定的最有效的两种增强潜伏指印的序列应用于伪操作试验，这两种序列应用于克莱兹代尔银行和苏格兰皇家银行的聚合物钞票（10 英镑和 5 英镑）上。 这两种增强序列被确定为最适合这些类型钞票的是聚氰基 UV 超级胶水蒸气处理，然后是黑色磁性粉末，以及黑色粉末悬浮液。 两种增强序列都包括增强前的荧光检查，以及白光处理后，再用红外线光处理。 Joannidis 等人进行的研究是在受控的实验室环境中进行的，在这种环境中，所有变量，即每个指印的位置和年龄都是已知和可控的。 然而，这些条件并不能准确反映聚合物钞票作为刑事调查一部分被扣押的情况。 因此，在伪操作试验中测试了两种最有效的增强序列，以确定它们在应用于模拟调查中扣押的钞票时是否同样有效。 为了模拟这些条件，从每家银行（每家银行都包含流通和未流通钞票的混合钞票）中取出 102 张钞票，让实验室工作人员在实验室中随意处理 4 周。 这项伪操作试验的结果证实了先前研究的结果。 发现超级胶水蒸气处理（使用聚氰基 UV），然后是黑色磁性粉末，可有效增强克莱兹代尔银行和苏格兰皇家银行聚合物钞票（10 英镑和 5 英镑）上的指印。 紧随其后的是粉末悬浮液，尽管其结果略逊于超级胶水和黑色磁性粉末，但也能有效地增强脊纹细节。 这项研究还证实，当拍摄任何脊纹细节时，红外线（730-800nm），加上 815nm 滤镜，可用于处理超级胶水和黑色磁性粉末的钞票，有助于减少背景图案干扰。
