Resulting line ratios if line emission flux purely from SF (blue stars) and purely from a LINER mechanism (orange point) are linearly superposed (coloured lines). The generating Hα flux ratios are colour coded. This shows that the SF contribution in the selected LINER regime right of the solid curve is negligible (F_SF/F_L < 0.2) and cannot be generating the discrepancy seen in radial emission line profiles with respect to a point-source illumination of >1 dex at larger radii.