Color excess E_B − V derived from the three DIBs as a function of the E_V − I value interpolated within the Sumi (2004) map at the locations of the target stars. E_B − Vs here are obtained using the Raimond et al. (2012) and Puspitarini et al. (2012, priv. comm.) average relationships based on FEROS data. The blue and pink dotted lines correspond to color excess relationships based on the Fitzpatrick (1999) and Cardelli et al. (1989) extinction curves and R_v = 3.1 (see text). In the case of the DIBs 6283.8 Å we also show the color excess values deduced from the Friedman et al. (2011) average relationships (open triangles).