Next: Cosmological Molecular Clouds Up: HST and the Previous: Cepheids in NGC . ... Recent calibrations of stellar surface brightness derived by modern observational interferometry show that the Cepheid PLC relations turn out to be much less affected by abundance effects than PL ones. Extragalactic Cepheid distances revisited by a calibrated PLC (V, V-Ic) relation indicate some significant systematic shifts affecting current PL determinations achieved by ground-based and HST photometry. ...