Qualitative analysis is performed by comparing unknown spark source spectra with reference spectra made from mixtures of metal oxides and salts with graphite. Quantitative evaluation is accomplished with a densitometer and added equipment that allows the analyst to choose any one of six methods of data treatment. The maximum blackening of the spectral line can be determined in terms of %T, 1−T, orI(ion density); or the line can be scanned while the blackening is integrated in terms of∫%T, ∫(1−T), or∫I. All measurements are read out in digital form. A method of internal system check, correction, and adjustment is described.