2. Materials and methods
2.1. Sample preparation
Fingerprints from three donors were deposited in triplicate on paper substrates of varying weight: mid-weight resume paper, cotton paper, magazine paper, and currency; standard weight copy paper; and low-weight newspaper. All substrates were decontaminated by UV cross-linking prior to use. Donors were asked to “charge” their fingerprints by rubbing their fingertips over their faces and necks to ensure that an abundance of epithelial cells and sebaceous oils would be present in the deposited fingerprints. A total of 162 samples were dried overnight at room temperature. For each collection technique, 54 latent fingerprints were sampled.