Relative changes, in percentage, of the Fe i equivalent widths ΔW/W caused by the impact of the model’s magnetic field versus the mean line-center optical depths. The ⟨ τ_{5(line center)} ⟩ values have been calculated at the line center of the lines using the snapshot with ⟨ | B_z | ⟩ = 0.5 G. Top panel: direct effect due to the ensuing Zeeman broadening of the Fe i lines. The equivalent width changes [W(B ≠ 0) − W(B = 0)] /W(B = 0) are the same as in Fig. 5. Middle panel: indirect effect caused by the magnetically induced changes of the thermodynamical properties in the formation region of the Fe i lines. Bottom panel: joint action of the direct and indirect effects.