Richness distribution in function of the S/N for the optical catalogues. PZWav is shown with grey dots, PZWav matches to VT are in red, and PZWav matches to the AMICO catalogue are in green. The matches between the three catalogues are indicated with x’s. The apparent wall at λ = 1.9 is produced by the richness cut described in Sect. 4.4. Lower λ values are from structures with z < 0.3, which are affected by another richness threshold.