Best fitting model of the H II region LF for regions with high (blue colors) and low (red colors) gas ionization parameters, q. Galaxies are ordered according to increasing stellar mass from top left to bottom right, and their names are indicated within each panel. The dashed and solid lines indicate the empirical LF and the best fitting model, respectively. The LF slopes are reported in the top-right corner of each panel following the same color scheme. The median ionization parameter, ⟨log q⟩, of the H II region parent sample, used to separate young and old H II regions, is indicated below each galaxy name in logarithmic units.