Comparison of the differential CMF (ΔN/ΔlogM) derived for the 558 candidate prestellar cores lying in areas of low background column density (, purple histogram) with the CMF of the 43 candidate prestellar cores lying in areas of high column density (, magenta histogram). Lognormal fits are shown in both cases, and have peaks at 0.4 M_⊙ and 3.8 M_⊙, respectively. Vertical dashed lines show the 80% completeness limits of the low and high column density samples at 0.33 M_⊙ and 1.3 M_⊙, respectively. The overplotted histogram in light blue is the CMF of all 804 candidate prestellar cores (same as in Fig. 13).