Centre for Forensic Science, WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, UK.
Forensic Sci Int. 2012 Jun 10;219(1-3):12-28. doi: 10.1016/j.forsciint.2011.11.011. Epub 2011 Dec 6.
This study investigates the enhancement of footwear impressions prepared with soils from different locations on a variety of fabric surfaces with different morphology. Preliminary experiments using seventeen techniques were carried out and the best responding reagents were evaluated further. Results indicated that the soils investigated (a cross-section of soils from Scotland) are more likely to respond to reagents that target iron ions rather than calcium, aluminium or phosphorus ions. Furthermore, the concentration of iron and soil pH did not appear to have an effect on the performance of the enhancement techniques. For the techniques tested, colour enhancement was observed on all light coloured substrates while enhancement on dark coloured fabrics, denim and leatherette was limited due to poor contrast with the background. Of the chemical enhancement reagents tested, 2,2'-dipyridil was a suitable replacement for the more common enhancement technique using potassium thiocyanate. The main advantages are the use of less toxic and flammable solvents and improved clarity and sharpness of the enhanced impression. The surface morphology of the fabrics did not have a significant effect on the enhancement ability of the reagents apart from a slight tendency for diffusion to occur on less porous fabrics such as polyester and nylon/lycra blends.
本研究调查了在不同形态的各种织物表面上使用来自不同位置的土壤制备的鞋印增强效果。使用十七种技术进行了初步实验，并进一步评估了反应最佳的试剂。结果表明，所研究的土壤（苏格兰土壤的一个横截面）更有可能对靶向铁离子而不是钙、铝或磷离子的试剂产生反应。此外，铁的浓度和土壤 pH 值似乎对增强技术的性能没有影响。对于测试的技术，在所有浅色基底上观察到颜色增强，而在深色织物、牛仔布和人造革上的增强由于与背景的对比度差而受到限制。在所测试的化学增强试剂中，2,2'-联吡啶是更常用的使用硫氰酸钾的增强技术的合适替代品。主要优点是使用毒性和易燃性较低的溶剂，并且增强后的印痕的清晰度和锐度得到改善。除了在聚酯和尼龙/莱卡混纺等多孔性较差的织物上稍微有扩散趋势外，织物的表面形态对试剂的增强能力没有显著影响。
