The convolution of fluid properties and surface force at fluid-fluid interfaces with large density and viscosity ratios and sizeable surface tension is a controversial and important issue. This study analyses and compares eight convolution strategies with respect to density, viscosity and surface force. The results prove the essential role of convoluted fluid properties for the numerical stability of cases with high density ratios (>= 10(3)) and demonstrate that convolution of the surface force, contrary to popular believe, neither enhances the predictive quality of interfacial flow simulations nor improves numerical stability. (C) 2013 Elsevier Ltd. All rights reserved.