Top panels: CMDs that best show evidence of more than one population, extracted from the central 5′ of the cluster. Fiducial lines for the apparent sequence split in the upper RGB are shown, together with the average error bars computed in bins 0.5 mag wide. Stars of the blue and red sequences are overplotted on the Hess diagram. Bottom panels: same as above for combinations of filters that are not much sensitive to light element abundance variations.