B − V vs. V − R (left) and V − R vs. R − I (right) diagnostic diagrams. The sample, comprising 202 unique objects with counterparts in the M05 catalogue is denoted by crosses (+). The red triangles (△) denote objects with spectroscopic redshift z_s> 0.5 in the M05 catalogue. The control grid has been built using synthetic colours from COSMOS templates for Sa, Sc, and SB galaxies in the range z = 0.0−1.0 with steps of Δz = 0.1. The thick black dashed line connects the three templates at z = 0.4. The blue dashed line depicts the Kodama et al. (1999) models at z = 0.4 and z = 0.5. The thick black solid line box marks the approximate region used for selecting the cluster candidates.