Comparison of the PLZ relations derived in this work with empirical PLZ relations provided by Vivas et al. (2017) for the globular cluster M5. Comparison is given for two distances to M5. Black lines: the PLZ relations derived in this work for a constant metallicity of [Fe/H] = −1.25 dex; gray, shaded areas: metallicity slope c_λ ± δc_λ from Equation (8); red lines: empirical PLZ relation from Vivas et al. (2017) for a constant metallicity of [Fe/H] = −1.25 dex and distance modulus equal to 14.44 mag; magenta lines: same as red lines but for distance modulus equal to 14.37 mag from Table 1 of Baumgardt & Vasiliev (2021).