Surface photographic photometry was not extended to low enough levels in order to warrant a suitable extrapolation leading to total magnitudes. We have computed, consequently, the luminosity up to the last measured isophote and we have obtained two parameters from the IS curve. Then, the values of N and Qₙ follow from double interpolation in a family of curves for integer values of N. Since Qₙ is known, we obtain the total luminosity Lₜ=QₙIₙSₙ and the total magnitude for each galaxy.Asociación Argentina de Astronomía