AbstractVarious experimental procedures for the determination of transient characteristics with significant liquid film effects were tested. A comparison between transient characteristics obtained experimentally and those calculated from rational models indicates that all procedures but one give highly inconsistent results. Recalculation of transient characteristics with no liquid film (easily measured in the gas phase) to that with liquid film (occurring in viscous liquids) is recommended as well as the selected experimental procedure which yields consistent results in the situations where the steady‐state probe reading is decreased up to one‐half due to the liquid f