Relationship between the flux densities measured within the four different pseudo-filters defined in this work on the best-fit model and those measured on the observed spectra. The solid line indicates the 1:1 relation. Blue filled squares, green triangles, red circles, and magenta crosses are for galaxies where the derived quenching factor is QF ≤ 0.5, 0.5 <QF ≤ 0.8, QF> 0.8, and early-type galaxies (all with QF = 1), respectively.