Spectral energy distributions of a selection of the long-duration GRBs with redshift in our sample, labeled on the right side. The X-ray spectrum has been extracted from early times, but after the rapid fading and excluding flares, and then shifted in mid-time to the GROND mid-time (see text for details). The dashed lines indicate the best-fit model for each burst, with the break between the X-ray and optical/NIR always treated as a free parameter. Curvature in the X-rays is due to Galactic plus host-intrinsic absorption, and curvature in the observed optical/NIR range due to host-intrinsic extinction (data have been corrected for Galactic foreground extinction before fitting). For better visibility, the intensity scaling has been choosen to minimize overlap of the different SEDs, and thus is completely arbitrary.