Color-coded Hα line profiles, which are marked by matching crosses in Fig. 4. The dashed black line represents the average of the color-coded line profiles. The thin, solid black line refers to an Hα profile of a pore, as indicated by the white asterisk in Fig. 4 inside pore P2. The thick, solid black line denotes the Kitt Peak FTS disk-center spectral atlas, which served as a reference in the wavelength calibration.