Line ratios between spectra at different limb positions and the spectrum taken at disk center for four example lines: Na I 5897, Mg I 5185, Ca I 6163, and Fe I 5384 (from top to bottom, panels span velocity ranges ±20, ±40, ±30, and ±30 km s⁻¹, respectively). The panels from left to right show observed IAG FTS spectra, and spectra for SME LTE, SME NLTE, and CO⁵BOLD calculations as dashed lines, respectively. For IAG FTS and SME spectra, limb positions μ = 1.0, 0.99, 0.98, 0.95, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2 are shown. The CO⁵BOLD models are available for μ = 1.0, 0.79, 0.41, 0.09. A darker color is used for spectra taken closer to disk center.