Colour − magnitude diagram: ^0.1(u − r) as a function of for galaxies in the field, in both low and high mass LGs, and in CGs. Equal luminosity samples of CGs and LGs are shown separately. Left panels include all galaxies in the samples, while right panels include only early-type galaxies according to their concentration parameter. Darker colours represent higher values. All distributions have been normalised to enclose the same volume.