Same as Fig. 3, where each of the 48 spectra were divided by a blackbody curve with the same parameters as the dotted red line in the top panel of Fig. 3, only re-normalised to the brightness of the respective spectrum. Wavelengths at which the ratio is below one indicate absorption lines; e.g., N VII at 24.8 Å, whereas wavelengthswith ratios greater than 1 indicate emission lines, that is, the same N VII or the N VI forbidden line at 29.1 Å duringthe dip. See Sect. 3.2.1 for details.