Fractional linear polarization profiles, Q/I (upper panels) and U/I (lower panels), for the core and near-wing region of the IR triplet lines for a LOS with μ = 0.1; from left to right, the 8498 Å, 8542 Å, and 8662 Å lines. The curves represent emergent profiles for syntheses with different uniform and horizontal magnetic fields with strengths in the B = 0 − 10 G range, as indicated in the legend. The reference direction for positive Stokes Q is the parallel to the nearest limb.