Background-subtracted cluster counts of red galaxies in J − Ks about the color of the SSP z_f = 3 model with a J − Ks color widths of ±0.1 mag (top panel) and ±0.25 mag (bottom panel) for the R ≤ 30′′ core region (red solid lines) and the full projected region within R₅₀₀ (blue dashed line) The characteristic magnitude Ks* at the cluster redshift is indicated by the green dashed line on the left, the solid/dashed/dotted vertical lines on the right mark the 100%/50%/10% completeness levels for the selected color interval. The sharp cut-off in the red galaxy counts at K ≃ 20.5 mag (≃Ks*+1.6) is clearly visible for all histograms.