Forensic Science Department, Henry C. Lee College of Criminal Justice and Forensic Science, University of New Haven, West Haven, Connecticut, USA.
J Forensic Sci. 2022 Jul;67(4):1476-1489. doi: 10.1111/1556-4029.15035. Epub 2022 Mar 29.
This research further expands previous studies in which color contrast between ridges and furrows was examined as a possible age indicator for latent fingermarks. Here, the variable biological sex and its influence on aging were investigated. A total of 756 sebaceous-rich impressions from seven males and seven females were deposited on glass and polystyrene plastic and aged in the dark for three months. At nine discrete times, random fingermarks were visualized with a titanium dioxide-based powder (TiO ), photographed, and edited in Photoshop® to collect pixel color data. Two color contrast-related metrics, mean color intensity (MI) and intensity amplitude (IA), were analyzed to determine whether the aging processes of biological male and female fingermarks were equivalent. These metrics revealed that impressions from the different biological sexes behaved in a similar manner over time. However, significant effects between substrates were observed. Quadratic regression models best represented the aging trends based on the MI and IA metrics for both male and female fingermarks. The correlation coefficients (R) and coefficients of determination (R ) were moderate to strong for impressions on glass but weaker for plastic. These findings indicated that biological male and female fingermarks could be incorporated into a single universal age estimation model per substrate when utilizing color contrast as an age indicator. Nonetheless, future studies are needed to better understand aging processes on plastic when using this methodology and to determine the life expectancy (i.e., the potential for identification) of latent fingermarks beyond three months.
本研究进一步扩展了先前的研究，即研究脊线和纹理之间的颜色对比是否可以作为潜在指印的年龄指标。在这里，研究了变量生物性别及其对老化的影响。总共从 7 名男性和 7 名女性身上采集了 756 个富含皮脂的印痕，将其沉积在玻璃和聚苯乙烯塑料上，并在黑暗中放置三个月进行老化。在九个不同的时间点，使用基于二氧化钛的粉末（TiO ）随机可视化指纹，拍照，并在 Photoshop®中进行编辑以收集像素颜色数据。分析了两个与颜色对比相关的指标，即平均颜色强度（MI）和强度幅度（IA），以确定生物男性和女性指印的老化过程是否等效。这些指标表明，不同生物性别留下的印痕随着时间的推移表现出相似的行为。然而，在基质之间观察到了显著的影响。基于 MI 和 IA 指标，二次回归模型最能代表男性和女性指印的老化趋势。对于玻璃上的印痕，相关系数（R）和确定系数（R ）为中等到强，但对于塑料上的印痕较弱。这些发现表明，当将颜色对比用作年龄指标时，可以将生物男性和女性指印纳入每个基质的单一通用年龄估计模型中。然而，需要进一步的研究来更好地了解在使用这种方法时塑料上的老化过程，并确定潜在指印在三个月以上的预期寿命（即识别的可能性）。
