The effect of handedness and biological sex on fingermark ridge height and volume as examined by 3D imaging.

For decades, detectives and forensic scientists have relied on friction ridge skin comparisons to identify individuals in criminal investigations. This method involves examining (latent) fingermarks, typically captured as two-dimensional (2D) images, and comparing them with known inked impressions or scans. The comparisons focus on general patterns, the location and orientation of minutiae, and additional characteristics like scars or pores. However, this common process overlooks other potentially valuable factors, such as handedness, biological sex, and the time since deposition, which could provide crucial investigative leads, especially in cases with partial or unclear ridge patterns. This study explored the potential of three-dimensional (3D) optical profilometry (OP) to observe changes in fingermarks ridge height and volume over 7 days while considering hand dominance and biological sex. The results indicated that all the assessed 3D metrics were generally consistent in detecting the effects of sex and handedness, mostly noticeable on aged fingermarks. Specifically, females and impressions from their non-dominant hand exhibited higher values. Additionally, the influence of time was evident, with fresh fingermarks showing significantly larger ridges in terms of height and volume. These findings suggest that 3D OP can enhance the probative value of fingermarks by inferring additional characteristics such as sex, handedness, and the age of the impression. These activity-level propositions could provide useful information in cases where only partial or poor-quality fingermarks are recovered, providing new data dimensions that could lead to more comprehensive forensic examinations.