Curves of growth for the Type 1 sample as described in Sect. 5. The solid black line shows the curve from the image obtained by collapsing the PSF-observation cube at the location of [O III] λ5007 channels. The Hβ BLR component is shown as a dashed black curve with the grey area showing the 1σ uncertainly. The BLR component is unresolved and serves as a proxy to determine the PSF during the observations which is also compared with the dedicated PSF star observation. The red curve shows the curve of growth for the total [O III] emission, meaning narrow and broad components. All the uncertainties are at 1σ levels. The BLR component is not plotted for X_N_66_23 as it remains undetected. For the rest of the Type 1 sample in the SUPER survey, the S/N is not enough to perform such a curve-of-growth analysis.