Colour–colour diagrams of galaxies in the Coma cluster with model predictions overlaid. Grey points show the Eisenhardt et al. (2007) data for galaxies in the Coma cluster. Panel a: XSL and E-MILES Padova00 models. (b) XSL PARSEC/COLIBRI and E-MILES BaSTI models. Only [Fe/H] = +0.2, 0.0, and −0.4 dex E-MILES models are shown. C18 models with [Fe/H] = +0.2, 0.0, and −0.5 dex models are denoted by solid blue lines. XSL models extend to even lower metallicities.