The quantum well states of a film can be used to sample the electronic structure of the parent bulk material and determine its band parameters. We highlight the benefits of two-dimensional film band mapping, with respect to complex bulk analysis, in an angle-resolved photoemission spectroscopy study of the 5d states of Au(111). Discrete 5d-derived quantum well states of various orbital characters form in Au(111) films and span the width of the corresponding bulk bands. For sufficiently thick films, the dispersion of these states samples the bulk band edges, as confirmed by first-principles calculations, thus providing the positions of the critical points of bulk Au in agreement with previously determined values. In turn, this analysis identifies several d-like surface states and resonances with large spin splittings that originate from the strong spin-orbit coupling of the Au 5d atomic levels.