Abstract
Understanding the physical, chemical and biological changes that occur
during the drying of a bloodstain is important in many aspects of
forensic science including bloodstain pattern analysis and time since
deposition estimation. This research assesses the use of optical
profilometry to analyze changes in the surface morphology of degrading
bloodstains created using three different volumes (4, 11, and 20 µL) up
to four weeks after deposition. We analyzed six surface characteristics,
including surface average roughness, kurtosis, skewness, maximum height,
number of cracks and pits, and height distributions from the
topographical scans obtained from bloodstains. Full and partial optical
profiles were obtained to examine long-term (minimum of 1.5 hour
intervals) and short-term (5 minute intervals) changes. The majority of
the changes in surface characteristics occurred within the first 35
minutes after bloodstain deposition, in agreement with current research
in bloodstain drying. Optical profilometry is a non-destructive and
efficient method to obtain surface profiles of bloodstains, and can be
integrated easily into additional research workflows including but not
limited to time since deposition estimation.