Some spectroscopic studies of lightning from 1901 to the present are reviewed, with special emphasis on slitless techniques—time-integrated and time-resolved. Some of the best examples of the authors’ time-integrated spectra are reproduced to display and identify emission and absorption features from 3000 Å to almost 9000 Å on a nearly uniform scale approximating 20 Å/mm. Time-resolved spectra in the visible region are reproduced in the range of milliseconds for a continuing-current luminosity, and microseconds for a return stroke and a stepped leader.
R. E. Orville and L. E. Salanave, "Lightning Spectroscopy—Photographic Techniques," Appl. Opt. 9, 1775-1781 (1970)