Fe I 6301.5 Å and 6302.5 Å profiles from observations and (non-)LTE inversions. Each column shows (from top to bottom) Stokes I, Q, U and V profiles as observed (coloured dots) and as fitted in LTE (grey dashed line) and in non-LTE (solid black line). The colour coding corresponds to the identically coloured plus markers in the left-hand panels of Fig. 2. The numbers above each column indicate the non-LTE-inferred B_los and B_hor at log τ₅₀₀ = −0.5.