Fig. 2

Raman spectra for bloodstain aging. Bloodstain aging was monitored at 30, 24, and 16 °C for up to 3 or 4 months. The Raman spectra were preprocessed by subtraction of fluorescence baseline and averaged for each time point. The blue and magenta lines indicate the Raman bands for which increases and decreases were visually observed over time, respectively. The yellow lines highlight the Raman bands at 376 cm⁻¹, which showed non-monotonic behavior over time. The spectral data of bloodstains collected from one of the three donors are represented