Two main effects control the clearances and pressures in rough elastohydrodynamically lubricated contacts. The first is the local attenuation produced by any relative sliding of the surfaces, the second is the clearance variation that is generated in the inlet and which moves through the conjunction at the mean surface velocity – the complementary wave. The first component, which is absent in rolling contacts, is relatively easy to estimate. The second is more complex, particularly in soft contacts, where, for sinusoidal waveforms, it may have a wavelength that differs from the original profile. In addition it will generally decay in amplitude during its transit through the conjunction. The paper explores this component and outlines some of the factors that determine its behaviour with both sinusoidal and more general roughness profiles.