Hierarchical Activities Designed for High-Resolution Visualization and Quantitative Analysis of Fingerprint Sweat Pores

Abstract

Level 3 characteristics are increasingly important for fingerprint identification, particularly when the fingerprints are problematic and lack level 2 details. In practice, no reliable visualization methods for level 3 features are transferred into a course for the general public, forensic students, or investigators. Our group has reported the membrane/water technique and wet-membrane method as simple, instantaneous, high-resolution, and reproducible methods for visualizing level 3 features of latent fingerprints (LFPs). Herein, we designed a simple-to-operate laboratory course on sweat pore visualization and analysis via the two methods mentioned. Three modules are included, and students participate in different modular combinations according to their interests and specialties. Module 1, consisting of a 15 min lecture on fingerprint theory followed by a brief demonstration of visualization procedures, is designed for broad audiences ranging from primary school to college laboratories. In module 2, students explored the deposition force impact on level 3 features (for students majoring in forensic science). Module 3 customized for forensic upperdivision undergraduates and postgraduates invites them to conduct Gaussian fitting of the pore area and adjacent pore distance. After discussion, students form their own opinions on the identifiable strengths of the above parameters in fingerprint matching. In a way, this experiment can be evolved into the elective course and specialized curriculum, where elective course containing module 1 can stimulate public interest in chemistry and specialized curriculum including modules 1−2 (or modules 1−3) may guide students to extract level 3 features and understand the role of level 3 features at a quantitative level.