Surface morphologies of electro-galvanized steel sheets were quantitatively characterized, and the relationship between the surface morphologies and the appearances were studied. First, the surface morphologies were directly connected to the appearances by comparing the laser microscope images with the scanning electron microscope images. Consequently, the relationship between the appearance and the surface morphology was qualitatively explained. Then the surface morphologies were measured using topographic scanning electron microscope and were quantitatively characterized calculating 3D parameters from the topographic data. The surface morphologies of the electrogalvanized steel sheets consisted of the shape of the Zn deposit and the roughness of the substrate. Extracting the shape of the Zn deposit from the surface morphology data by means of high-pass filtering, 3D parameters according with the qualitative explanation were obtained.
