Spatially resolved NLTE equivalent width correction at disk-center intensity (μ = 1), shown for representative lines of Li i (6707 Å, top left), Al i (3961 Å, top right), Ca ii (3933 Å, bottom left), and Fe i (3719 Å, bottom right) in a high-resolution snapshot of the hydrodynamical model (240² grid points for Li, Al and Ca; 120² for Fe). Although the behavior is shown for vertical rays, we emphasize that the statistical equilibrium was solved using the 3D radiation field. The NLTE line strength correction, Δlog W_{λ,μ = 1} = log W_{λ,μ = 1}(NLTE)−log W_{λ,μ = 1}(LTE), corresponds roughly to the abundance correction but with opposite sign. Red and blue colors indicate weaker and stronger lines under NLTE than under LTE, meaning positive and negative abundance corrections. For this illustration, we adopt the abundances A(Li) = 0.70, A(Al) = 1.15, A(Ca) = −0.62, and A(Fe) = 0.60. Na, not shown, behaves very similarly to Li, and the corresponding illustration for Mg is shown in the bottom left of Fig. 4.