Sunspots used for the chromospheric-line analysis. Upper panel: Line-wing images showing the (pseudo-)photospheric appearance of the spots. Contours derived from intensity thresholds outline the umbra (white) and penumbra (red). Lower panel: Same fields of view shown in the respective line cores, probing the chromosphere at different heights. The same contours are overplotted to highlight the chromospheric contrast of the umbra, penumbra, and surrounding quiet Sun.