Absolute neutron capture cross sections for natural elements of copper, yttrium, zirconium, niobium, lanthanum, gadolinium, terbium, tantalum, tungsten, rhenium, platinum, thallium, bismuth, and separated isotopes of 63Cu, 65Cu, 155Gd, 156Gd, 157Gd, 158Gd, 160Gd, 182W, 183W, 184W, 186W, 203Tl, 205Tl have been measured in the 0.5- to 3.0-MeV energy range. For most of these nuclides and isotopes, available data were scarce and discrepant, especially for neutron energies above 0.7 MeV. A spectrum-fitting method was developed to deduce the radiative capture cross section from prompt gamma rays emitted by the sample. The gamma rays were recorded by a NaI scintillator surrounded by an annular detector and the capture gamma-ray spectrum was obtained by unfolding the observed pulse-height distribution with the response function of the detector. Gamma-ray spectra emitted in the capture of 0.5-MeV neutrons as well as the multiplicity of the gamma-ray transitions are presented.