Optical studies of amorphous carbon films, deposited at liquid nitrogen and room temperature, by ion beam sputtering of a graphite target onto several crystalline and amorphous substrates, are reported. Room temperature Raman spectra of hydrogenated and unhydrogenated films are presented. Spectra of laser annealed films and carbon black composed mainly of microcrystals of graphite are also included. A comparison of these spectra with recent model studies is discussed. In addition the effect of pressure on the absorption edge tail was measured. The results are consistent with a model of amorphous carbon in which there is a network structure of both three-fold and four-fold coordinated atoms.