[en] We have calibrated a self-consistent set of multigamma-ray standards using the automated multi-spectrometry γ-ray counting facility at LLNL's Nuclear Chemistry Division. Pure sources of long-lived activity were produced by mass separation and/or chemical purification. The sources were counted individually and in combination on several different calibrated spectrometer systems. These systems utilize various detectors ranging from small (x-ray) detectors to large volume high-purity Ge detectors. This has allowed the use of the most ideal individual detector-efficiency characteristics for the determination of the relative γ-ray intensities. Precise energy measurements, reported earlier (Meyer, 1976) have been performed by an independent method. Both the energy and γ-ray-emission probabilities determined compare well with independently established values such as the recent ICRM intercomparison of ¹⁵²Eu. We discuss our investigations aimed at resolving the shape of the efficiency response function up to 10 MeV for large volume Ge(Li) and high-purity Ge detectors. Recent results on the γ-ray-emission probabilities per decay for ¹⁴⁹Gd and ¹⁶⁸Tm multigamma-ray sources are discussed. For ¹⁶⁸Tm, we deduce a 0.01% β^- branch to the 87.73-keV level in ¹⁶⁸Yb rather than the previous value which was a factor of 200 greater. In addition, we describe current cooperative efforts aimed at establishing a consistent set of data for short-lived fission products. Included are recent measurements on the bromine fission products with γ rays up to 7 MeV