Evolution of the CMR intercepts in (U − V) at M_V − 5 log  h = −20 for red-sequence galaxies as a function of redshift. The solid line is a least-square fit to the VIPERS data including the local SDSS reference (filled black square). The blue area reflects the total observed scatter due to systematic uncertainties, whereas uncertainties due to Poisson noise are indicated with single error bars. The grey shaded area shows the observed measurement errors of the COMBO-17 data set by Bell et al. (2004b). In the bottom left corner typical uncertainties due to filter and rest-frame transformations are shown.