A: radial colour profiles in g − r and i − H (same as in Fig. 1) for all 12 quantitative blue-cored (g − r gradient >0.10 mag/R_eff) early-type dwarf galaxies. B: radial colour profiles of the four galaxies that were classified as qualitative blue-cored early-type dwarf galaxies by Lisker et al. (2006b), but which we found to have clearly smaller g − r gradients than 0.10 mag/R_eff. C: four normal early-type dwarfs for comparison.