To characterize patterns of non-monotonic decay we measured the total integrated intensity of all reflections across multiple dose series from different crystals (Fig ). The derivative in summed intensity for all measured reflections was calculated as a function of fluence, during increasing beam exposure. Derivative profiles are anticipated to maintain a near constant, negative value in the event of radiolytic damage-induced monotonic intensity decay. Instead, we observed varied behavior depending on the type of crystal studied. In crystals of biotin, Cu(II)-serine, and Zn(II)methionine, derivative profiles showed an initial period of dynamic fluctuation before approaching a constant negative value, where monotonic decay prevailed, most often by the time 0.5 e -/Å 2 had been delivered at 200 kV (Fig. ). The distinction between these two regimes of intensity changes is evident in discretized plots of the derivative profiles, and led us to hypothesize that these crystals undergo an early period of dynamic change followed by global monotonic decay. In contrast, for the beam-resistant samples we studied, the hardiest of which was Co(II)-porphyrin, derivative profiles were consistently negative and near constant (Fig. ). These trends were mirrored in plots of the standard deviation of derivative profile values averaged across multiple crystals of a given sample. When observed, the changes were consistently most prominent within the first 0.5 e -/Å 2 of irradiation at room temperature for beam-sensitive crystals (Fig 1B ).