Median values of E_B−V used to produce the synthetic catalogues vs. that found with the FOSC for dwarfs (top) and giants (bottom). The error bars give the value of the first and third quartile of the distribution for each bin. The solid black line materialised perfect correlation and the dotted lines show the ± 10% interval around it. The colours of the symbols correspond to the different runs, as indicated. The synthetic magnitudes reproduce the characteristics of the Obscat catalogue.