title: Latent Fingermark Aging Patterns (Part III): Discontinuity Index as One Indicator of Degradation.
abstract: This article is the third in a series of reports exploring quantifiable visual parameters of the aging process of latent fingermarks. On this occasion, research is focused on the occurrence of ridge discontinuities (i.e. breakages) as a function of time. Experiment variables included type of secretion (eccrine and sebaceous), substrate (glass and plastic), and exposure to natural light (dark, shade, and direct light) over a 6 months period. Fingermarks were sequentially visualized with titanium dioxide powder, photographed, and the number of naturally occurring ridge discontinuities subsequently evaluated. A semi-quantitative value, named Discontinuity Index, was used to better characterize this aging parameter. Results indicated that ridges of sebaceous depositions on glass were generally less affected by the environmental conditions compared with those on plastic surface. In addition, aging in darkness was not always the best condition for preservation, and the direct exposure to light seemed not to affect the degradation under certain conditions.
authors.affiliation: New College of Interdisciplinary Arts and Sciences, School of Mathematical and Natural Sciences, Arizona State University, 4701 West Thunderbird Road, Glendale, AZ 85306.
authors.forename: Josep
authors.initials: J
authors.lastname: De Alcaraz-Fossoul
authors.affiliation: Legal Medicine Unit, Faculty of Medicine, University of Barcelona, C/Casanova 143, 08036 Barcelona, Catalonia, Spain.
authors.forename: Carme
authors.initials: C
authors.lastname: Barrot Feixat
authors.affiliation: Legal Medicine Unit, Faculty of Medicine, University of Barcelona, C/Casanova 143, 08036 Barcelona, Catalonia, Spain.
authors.forename: Clara
authors.initials: C
authors.lastname: Carreras-Marin
authors.affiliation: Legal Medicine Unit, Faculty of Medicine, University of Barcelona, C/Casanova 143, 08036 Barcelona, Catalonia, Spain.
authors.forename: Jack
authors.initials: J
authors.lastname: Tasker
authors.affiliation: Department of Applied Forensic Sciences, Mercyhurst University, 501 East 38th Street, Erie, PA 16546.
authors.forename: Sara C
authors.initials: SC
authors.lastname: Zapico
authors.affiliation: Legal Medicine Unit, Faculty of Medicine, University of Barcelona, C/Casanova 143, 08036 Barcelona, Catalonia, Spain.
authors.forename: Manel
authors.initials: M
authors.lastname: Gené Badia
keywords: aging; dating; discontinuities; forensic science; latent fingerprint; morphometrics; parameters; titanium dioxide