The growth of blisters caused by water transport induced by dosed amounts of salt inside the blister is studied. The process of water transport through the film was calculated by applying the laws of osmosis and compared with the transport of water through free films of the same varnishes. The results showed that for polyurethane, epoxy and chlorinated rubber films on stainless steel the volume of the blister was determined by the amount of salt deposited on the sub-strate and diffusion and sorption properties, but was independent of the adhesion and viscoelasticity of the films. -- AATA