Generation of synthetic V vs. B − V CMDs. Panel a) the adopted isochrone shifted by distance modulus and reddening. Panel b) the distribution of stars in accordance to the IMF and the fraction of binaries. Panel c) the introduction of photometric errors in magnitude and colour. Panel d) colours following the density of points in the CMD in a logarithmic scale. The density of points is related to p_CMD,i (see Sect. 3.2). The reddening vector and the values for all physical parameters are shown in the figure.