Figure 1. Topographical scans of the top and side of one 4 µL bloodstain at varying times since deposition up to 4 weeks. The scans show the height (μm) against the X-distance (μm) on the plate. The corresponding height profile is taken from the vertical/horizontal slice of each scan over time is also shown (bottom right).

3.2 Short-Term Experiment

Topographical scans for the short-term experiments indicate that in the first ~15 minutes, the bloodstain changes from a liquid sessile drop to a soft-solid as more of the bloodstain can be detected by the profilometer (Figure 2). After the bloodstain had dried, the formation of the rim was observed, indicating that the majority of the RBCs had moved to the outside of the bloodstain (Figure 2, 15 minutes). The formation of cracks occurred between ~20-30 min, and after ~35 minutes after deposition, there were no significant visual changes in the subsequent scans (Figure 2).