The effect of pulp chemistry and the presence of solids on a froth bubble size measurement method developed by Bhondayi and Moys (2014) was tested. Three conditions representing different pulp chemistries and two solids loading conditions were investigated. Bubble size measurements were performed in both a laboratory mini flotation column and a mechanical cell. Results established that estimates for bubble sizes from the new method termed intra-bubble impact distances (IID) can be measured irrespective of the pulp chemistry and also that the presence of solids does not affect the method. The IIDs were on average higher than the Sauter-mean diameter which agrees with results reported by Bhondayi and Moys (2014). Although the presence of solids precluded comparison with the photographic method in the mechanical cell, at low solids content (mini-flotation column) a linear correlation existed between average IIDs and Sauter-mean diameter obtained from photographs. The presence of significant amount of solids (mechanical cell tests) changed coalescence dynamics as shown by a deviation from a linear correlation observed with low %solids and two-phase systems. (C) 2016 Elsevier B.V. All rights reserved.