Relative differences in the temperature (left) and density (right panel) stratification vs. the (averaged) Rosseland optical depth for various stellar parameters. The differences are relative to the Rosseland optical depth, i.e. . Orange/brown dashed lines: averages on layers of constant geometrical height ⟨3D⟩_z; orange/brown dotted lines: averages on layers of constant column mass density ⟨3D⟩_m; orange/brown solid lines: 1D MLT models. Blue solid lines: flux-weighted T⁴-stratifications; blue dashed lines: brightness temperatures T_rad averaged on surfaces of constant Rosseland optical depth (left panel). Green solid lines: logarithmic density averages ; green dashed lines: hydrostatic averages (right panel). We compare always cooler and hotter effective temperatures, which are distinguished by dark and bright colors respectively. We note that the cool metal-poor dwarfs exhibit very small differences, and are therefore indistinguishable. Note the differences in the y-axes.