Normalized distribution of the ratios between the recovered and the spectroscopically measured Hα + [N ii] flux for S1 spectra, with the SED-fitting routines. Empty red histogram shows the results after SED-fitting method without r’ decontamination. Dashed blue histogram denotes the results after SED-fitting method with r’ decontamination. Solid curves indicate Gaussian fits to the distribution of R. The best fitting values are labelled in the panel.