The first part of this paper focuses on the mechanisms of particle accumulation and depletion from the membrane near-field region by studying Residence Time Distributions (RTDs) obtained at the concentrate side in response to impulse inputs of monodisperse suspensions. A previously published trajectory equation is evaluated by comparing theoretical predictions and experimental measurements of first and peak transit times as well as peak heights. Diffusive back-transport is studied semi-quantitatively in terms of second peaks in RTDs. For a given set of of hydrodynamic parameters, differences in transport characteristics because of differences in particle size can lead to changes in the particle size distribution (PSD) between a polydisperse feed suspension and the deposited cake. We also report experimental data on transient flux behavior and PSDs in a lab scale parallel plate membrane filter with one solid wall. Only laminar flow systems are considered in this paper and in all cases particles are larger than the membrane pores so as to prevent pore penetration and subsequent membrane fouling.