5. Conclusion
Optical profilometry provided detailed topographical scans of degrading whole bloodstains, an area not yet explored in the forensic literature. We were able to characterize the drying of three different bloodstain volumes through the analysis of relevant surface characteristics. Importantly, this work investigated the timewise degradation of whole blood, expanding on previous work that explored the drying of blood and other biocolloidal fluids. Using this method, we observed that most of the timewise changes to drying bloodstains occur within the first 35 minutes after deposition. Over a longer time period, the overall surface morphology shows little variation, currently limiting the use of optical profilometry as a standalone technique in TSD estimates. Optical profilometry has previously been paired with SEM [24] and AFM [25] for imaging purposes; combining these two techniques could be useful for a more detailed analysis of crack and pit formation. In addition, factors such as viscosity, temperature, PCV%, and blood diseases affect the drying of bloodstains [8,9,11,26]. Further research into these factors should be undertaken to understand their effects on the topography of degrading bloodstains [8,9,11,26]. Additionally, the influence of topography on spectral changes for TSD estimation should also be considered. Finally, various substrates, such as those with rougher surfaces, may lead to interesting crack formation and timewise trends with bloodstain degradation that could be captured using optical profilometry.