Evolution of PN models in the V_HWHM−M(5007) plane. Shown are nebular sequences around central star models of 0.696 and 0.625 M_⊙, each of which started with the same initial model but with three different metal contents, as indicated in the figure legend. These sequences are supplemented by ones with less massive central stars of 0.605 and 0.595 M_⊙, both with hydrodynamically computed initial envelopes (cf. Table 2). The abscissa gives either the [O iii] magnitude M(5007) as defined by Jacoby (1989) (top) or M(5007)−M ^⋆ , with M ^⋆  = −4.48 (bottom). The evolution proceeds from low velocities and faint magnitudes over medium velocities and bright magnitudes towards high velocities and again faint magnitudes. The models are compared with a large data set of bright PNe belonging to a variety of galaxies (or parts of them) as indicated in the legend and extracted from Richer (2006, Fig. 4.