MHD-HD difference of the temperature stratification obtained for layers close to photospheric line-forming regions after averaging horizontally on surfaces of equal optical depth and temporally over the (63 × 63 column) input snapshots used in the spectral synthesis. Blue, green and red lines represent the difference in temperature with respect to the HD case, against log ₁₀τ_{(500   nm)} (bottom horizontal axis), for the 50 G, 100 G and 200 G cases, respectively. The top horizontal axis shows the corresponding physical depth in Mm in the HD case.