Observed and simulated Ca II K images of the quiet Sun at the disk center (μ = 1). Upper row: line wing at Δ λ = −0.528 Å is shown. Lower row: line center at Δ λ = 0 Å is shown. SST/CHROMIS images (first column) are compared with simulated images using Model 3, 2, and 1 (second, third, and fourth columns). Images are given in brightness temperature units with scales common for each row, specified at the right. The rms contrast R is provided in the upper right corner above each image. The red line indicates the slice through Model 2 shown in Fig. 15.