Co-added spectra of PNe in M83 and M94, as a function of [O iii] absolute magnitude and [O iii] λ5007/Hα+[N ii] flux ratio. The abscissa plots wavelength; the ordinate shows relative counts, with the red portion of the M83 spectra reduced by a factor of 2 to correct for the higher system throughput. The spectra with I(λ5007) ₀/ I(Hα+[N ii]) ₀ > 2 have been co-added in the upper rows, while those with a flux ratio <2 have been co-added in the lower rows. The spectra are remarkably similar: the only obvious change is the increased importance of [N ii] in lower luminosity objects.