Color−color diagrams discussed in the text. We use the color measurements obtained using the approach 1. The colors are corrected for Galactic extinction. The arrows indicate the reddening vectors (the length correspond to 0.1 mag extinction in the r-band). The black circle represents the mean color of the elliptical galaxies from Shimasaku et al. (2001). The black star and the black downward triangle represent the mean colors of S0−Sb and Sbc−late-type galaxies from Muñoz-Mateos et al. (2009), respectively.