WFI V − I vs. B − R colours for all of the extracted sources with R magnitudes ≤ 24. The dashed blue and black lines show the colour cuts defining the box we used for target selection. Small black and green dots are the sources classified as galaxies and stars in the WFI photometric catalogue, respectively. Larger data points mark cluster member galaxies in black and non-members in red that belong to our CLASH-VLT spectroscopic catalogue.