Line strengths of two hydrogen line indices, Hβo in the optical (upper panel) and Pa_β1.28 in the NIR (lower panel), plotted against the total metallicity indicator [MgFe]′ for two samples of GCs in the Cen A galaxy (blue points) and MW (red squares). The overlaid grids represent predictions from updated E–MILES SSP models with BaSTI and Padova isochrones (solid and dotted lines), as well as E–MILES SSPs with [α/Fe] = 0.0 and +0.4 (dashed and dash-dotted lines). These models span a range of metallicities from Z = −2.27 (−2.32) to solar, as indicated by various colours, and ages ranging from 5 to 13 Gyr (12.59 Gyr) for SSPs with BaSTI (Padova) isochrones.