Distribution of colors measured over different regions of the galaxies – total color down to the Holmberg radius r_H (top row); central colors down to μ_B = 24 mag arcsec^-2 (second row); color in the region 24 ≲ μ_B ≲ 26 mag arcsec^-2 (third row); color in the region 26 ≲ μ_B ≲ 28 mag arcsec^-2 (last row). The bin sizes are 0.1, 0.05, 0.05, 0.1, 0.2 for U − B, B − V, V − R, V − I, and V − K respectively, making the bin sizes greater than or equal to the average errors in the colors in the first row (Table 4). The G^B and G^R groups in the text are marked with blue and red.