Comparison between the Stokes profiles computed in LTE and NLTE at the four sample pixels P1, P2, P3, and P4 indicated in Fig. 1. The black curves are computed in LTE. The blue curves are computed by treating only iron in NLTE. The red curves are computed by treating Fe as well as Si, Al, and Mg in NLTE. The four columns show Stokes I/I_c, Q/I_c, U/I_c, and V/I_c, expressed as percentages, where I_c is the spatially averaged continuum intensity over the non-spot region of the cube. The six vertical lines give the positions of the grid points sampled by HMI onto which the Stokes profiles are interpolated in Fig. 7. The numbers in the bottom right corner of each panel are the δEW, δQ_max, δU_max, and δV_max, respectively, for the profiles in red and blue.