By means of hydrogenography and an yttrium indicator layer we determine the intrinsic hydrogen permeability in hundreds of compositions of the PdyCu1-y alloy, under exactly the same experimental conditions of temperature and hydrogen pressure. The permeability values obtained with this technique are intrinsic in the sense that they are independent of surface reactions. The room temperature values of the permeability of PdyCu1-y with 0.3 < y < 0.7 exhibit a clear maximum near y = 0.47. The same technique is easily applicable to determine the intrinsic hydrogen permeability of the ternary or quaternary alloy systems. This is explicitly shown for the Pd-Cu-Mo ternary alloys. In this system addition of Mo always leads to a decrease of the intrinsic hydrogen permeability. A similar behavior is observed for Pd-Cu-Ta and Pd-Cu-Ti ternary alloys. (c) 2013 Elsevier B.V. All rights reserved.