The intensity at t = 0.2 s could have been manually compared to the standard deviation of normalized intensities, but we opted for a more elegant automated solution using UMAP dimensionality reduction. In essence, all individual curves from Figure , representing normalized intensity vs. time, were truncated at predefined cut-off times and transformed into single points in a new coordinate system defined by UMAP axes 1 and 2 (see the SI-2, 5 and 6 for technical details). According to the rules of this transformation, curves with similar patterns are represented as a single cluster of points, while distinctly different patterns, such as those associated with pitting, form separate clusters. This behavior is precisely observed in the UMAP projection shown in Figure . At the cut-off time of 0.2 s, only one cluster of points is visible, indicating that the small decrease in intensity at this time remains within the standard deviation of normalized intensities. However, at the cut-off time of 0.4 s, two distinct clusters appear, with the new cluster, depicted in orange, corresponding to pit formation.