Fractional linear polarization profile Q/I for the core and near-wing region of the IR triplet lines for the disk-center LOS (μ = 1); from left to right, the 8498 Å, 8542 Å, and 8662 Å lines. The curves in the upper panels represent emergent profiles for syntheses with uniform and horizontal magnetic fields with strengths in the B = 0 − 10 G range, as indicated in the legend, whereas lower panels show results in the B = 100 − 1000 G range. The reference direction for positive Stokes Q is the perpendicular to the magnetic field.