Yields of 24 radioactive nuclides formed by the interaction of bremsstrahlung with maximum end-point energies of 100 MeV--1 GeV with Cu have been measured by direct ..gamma..-ray counting of irradiated targets. The yields in the mass range of 42 to 60 (except for /sup 60/Cu) were analyzed by a nonlinear least-squares fit to obtain the mass yield and charge dispersion curves in spallation reactions. From the parameter values obtained, the energy dependence of the slope of the mass yield curve and the relationship between target N/Z and the most probable product N/Z were investigated and compared with the results of proton, ..cap alpha.., and heavy-ion-induced spallation of Cu. The characteristics of photon-induced spallation are discussed.