For what is regarding the role of the instrumental set-up, that is of its transfer function, this function had to be deconvoluted from the recorded spectra . The true spectral distribution, which is subjected to "distortions both in the optical and recording parts of the apparatus" , is replaced by the observed measured distribution. This is a further reason to stress once more that there is no a priori reason to choose a particular function to fit the spectrum, especially if we have not determined the instrumental transfer function.