Lyα/Hα ratio against the Hα/Hβ luminosity ratio for the in Sect. 4 analysed subsample of 33 galaxies as. there is no correlation between both quantities (τ = −0.09/p_τ = 0.47). Symbols, colouring, and highlighting of the symbols is the same as in Fig. 13. The expectation of Lyα/Hα as a function of Hα/Hβ for a homogeneous dust-screen without radiative transfer effects in front of the line emission is shown as a solid line (Eq. (6)). The curves with a colour gradient indicate possible values for Lyα/Hα and Hα/Hβ for a clumpy dust screen, where on average N_C = {3, 7, 9} clumps block the sight lines (Eq. (9)). These lines are drawn with a colour gradient that indicates the dust optical depth τ_C at 1216 Å of a single clump (colour bar at the top of the plot).