Relation between the color index (g*−i*) and the concentration index in the r* band, C(r*). Open squares denote E galaxies. Asterisks denote early‐type galaxies (S0–Sa). Crosses indicate galaxies of "intermediate"‐type (Sb–Sc). Open circles stand for late‐type galaxies (Sd–Irr and dI). Filled lozenges denote dEs. Filled triangles denote interacting galaxies. The values of the concentration index for classical de Vaucouleurs profiles (5.5) and for pure exponential disks (2.3) are shown by dashed lines.