PbS, PbS(KMnO4), PbS(NH4I), PbS(KMnO4, NH4I) films with good adhesion to a glass substrate with a thickness of 250 to 490 nm were obtained by chemical deposition. Their composition, morphology, and photosensitive properties have been studied. Comprehensive studies using Raman, IR, and Auger spectroscopy established the presence on the surface of the films of a number of impurity oxygen-containing phases (PbO, PbCO3, PbSO4) and cyanamide PbCN2. A synergistic effect of increasing the photoresponse of PbS films synthesized in the presence of a combination of KMnO4 and NH4I additives was revealed, which is due to the formation of an optically active phase of diiodine pentoxide I2O5 on the crystallite surface. Elemental analysis during layer-by-layer ion etching suggested the formation and incorporation of PbSO4, PbCO3, and PbCN2 into the PbS(KMnO4, NH4I) film, and PbCN2 into the PbS(KMnO4) film.