We report that spray pyrolyzed CdS has a luminescence spectrum that dramatically changes with incident photoexcitation energy. Over the photoexcitation range between 1.94 eV and 2.71 eV, the intensity of the 1.22 eV (1020 nm) luminescence line is constant, but that of the 1.55 eV (800 nm) luminescence line first increases, then decreases, and then remains constant. These results are used to measure the 1.55 eV line trap energy of 1.90 eV, and to demonstrate the role of localized carriers in the 1.55 eV line trap cross-section.