Histogram of the extinction toward the stars detected in W3 Main with a bin size of 0.2 mag. Using the Nishiyama et al. (2009) extinction law, the stars are de-reddened in the CMD on to a 2 Myr main sequence and PMS isochrone. Changing the isochrone to 1 or 3 Myr does not change significantly the shape of the histogram. The solid line shows the histogram of the extinctions derived toward stars with JHK_s detections, while the dashed line represents the extinction histogram of all the HK_s sources (including the JHK_s sources). The vertical dotted line denotes A_Ks = 0.4 mag and shows the division line between the foreground and the cluster population.