Fig. 2

RH gradients for the crystallization and dissolution experiments (respectively red and blue curves). The horizontal dotted line at 75.34% indicates the RH_eq of NaCl at 20 °C. The average time (first recorded datapoint) for the equipment to reach below the RH_eq is shown as the red dot (including error bars). The horizontal error bar shows how the equipment needs more time to reach the RH_eq during the crystallization experiments, with 0:05:53 for the experiment form 90 to 70% RH and less than a minute for the following experiments. The considered interval times (from t₁ to t₅) are shown as an example and explained in text above