The effects of resin blend or solvents on a deposited film in an electropaint system were studied. We confirmed that the film formation follows the ion-permeable film formation (IPFF) model. The film resistivity fell off after the addition of a resin with a low glass transition temperature (T-g) to a resin with a high T-g, and the deposition behavior was similar to that of the resin with low T-g, which is deposited like a conductive film. Blending the resins caused an effect in which the resin with low T-g acts as a conductive bonding material, filling interstices between particles composed of the resin with high T-g (the resin blend effect). When a solvent (ethylene glycol monobutyl ether) was added to the resin with high T-g, the deposition resulted in a highly conductive film. The solvent molecules were adsorbed on the disperse particles and promoted coalescence of the particles in the deposited film. Thus, the thickness of the continuous layer was increased (the solvent effect). The effect of solution temperature was also similar to the solvent effect. All the results supported the IPFF model. The model gave a satisfactory explanation for the solvent effect, which was difficult to explain with the porous film formation model. (C) 2003 The Electrochemical Society.