We report gold photocurrent and reflectivity measurements made at the Daresbury Synchrotron Radiation Source. We find that the measured M-edge energies differ from tabulated values by about 30 eV for the MIV and MV edges. The effect is also apparent in Pt and Pb and in literature reports for Ir. We attribute the discrepancy to the use of limiting absorptions based on X-ray photoelectron spectroscopy (XPS) values. For the MIV and MV edges, the differences are accentuated by the very slow onset of the 3d → f transition. An analysis of the partial density of states not only identifies the relevant transitions, but also reveals the origin of X-ray absorption fine structure (XAFS) around the edges. These results are of importance for the calibration of astronomical X-ray mirrors and gratings.