Maps of the continuum intensity for AR 10923 observed on 14 November 2006 (left) and for AR 10969 observed on 27 August 2007 (right). The white contours indicate a continuum intensity of 50% of the quiet Sun level. The other contours correspond to B_crit(log τ) inferred for the different nodes in the inversion (see Table 2). Blue: log τ = 0, green: log τ = −0.9, and yellow: log τ = −2.5. The red contour represents an inversion, where the magnetic field is independent of height, and shows a value of 1867 G. The field-of-view of the two panels is indicated by the white boxes in Fig. 1. The size of the field-of-view is the same in both panels.