Ratio of the Hα to Hβ luminosity for our set of models, adopting only H I lines in the spectrum calculation. Values are scattered, reflecting the influence of intrinsic optical depth effects and the non-thermal process of formation of these lines. This ratio ignores optical depth effects caused by other elements such as iron. Consequently, in the total emergent spectrum (resulting from the contribution of all elements and ions), this ratio is much greater, and potentially infinite.