Departure coefficients b = n/n_LTE of the levels involved in the 8718 Å line, 7d (blue) and 4p (red). Left panel: metal-poor dwarf case, right panel: metal-poor giant case. The insets show the corresponding line profiles. Note that in the giant case, abundance corrections corresponding to some models for which b are shown here are not shown in Fig. 10 because the models did not converge for at least three abundance values.