The spectral dependences of PbSe optical constants have been obtained by Kramers-Kronig analysis of the reflectance data in the energy range 1 to 4 eV. The thermoreflectance spectra of PbSe films, grown by two different techniques-hot wall epitaxy and laser-assisted deposition, have been investigated in the same energy range at temperatures 40, 80, 100, 200 and 300K. As a result of the quantitative interpretation of these spectra a detailed assignment of the energy levels has been obtained. The simultaneous investigation of the films grown by two different techniques has enabled their optical properties to be compared and some conclusions concerning the laser deposition technique to be drawn.