When the voltage applied to an electrolysis cell is high enough, electrode effects (either anode effects or cathode effects) are mostly accompanied by rather strong light emission. The use of spectroscopic methods is then an appropriate diagnostic approach. Independently of descriptive studies and the plotting of voltage-intensity relationships, the authors investigated the calculation of theoretical line shapes in order to determine the principal parameters of the electrolytic plasmas produced during the occurrence of the electrode effect. This study referred in particular to the experimental shape of the semi-degenerate Li I (4₧4 d4 p→ 2 p) line, recorded during the occurence of the anode effect in an equimolar mixture of molten LiCl and KCI. A calculation as exhaustive as possible entailed the necessity to superpose profiles. The latter, which correspond to given values of the parameters, were termed “instantaneous shapes”. Their superposition was accomplished by considering Paschen curves of the distribution of disruptive voltages of the mixture of gases that forms an insulating sheath gas. The calculation of “instantaneous line shapes” underlying the resultant profile again uses the previous computation routine (Magnus frame and effect of dynamic broadening) and yields theoretical line shapes that link up well with the experimental ones. In addition, this study gives a more precise physical interpretation of the anode effect.