Simulated images of Ca II 8542 Å, Ca II K, Mg II k, and Hα from the model atmosphere in vertically emergent intensity. Top row: at nominal line center, Δλ = 0 Å. Bottom row: at wavelengths corresponding to the maximum formation height, maxz(τ = 1). Intensity is expressed as brightness temperature T_b and is clipped to same ranges in each column: 3.6–7 kK for Ca II 8 542 Å, 3.6–7 kK for Ca II K, 3.6–8 kK for Mg II k, and 3.6–10 kK for Hα. The minimum, maximum, and average T_b for the entire FOV is provided in a label above each panel. Colored symbols indicate the following structures: a dark fibril (red dot) and a flare ribbon (blue dot), see Fig. 4; an active region in emission (orange cross), see Fig. 12; an active region in emission with a strong velocity gradient (blue cross), see Fig. 13; a sunspot (green cross), see Fig. 14; a fibril (red cross), see Fig. 15.