A comparison of the k-approximation and the l-approximation of the blackening curves of some photographic materials for spectrography

Abstract The experimental and computed blackening curves of some Orwo spcctrographic plates are compared. In spectrochemical applications, the two approximation equations are found to give equal errors. In optimizing the photographic registration of spectra the l -approximation equation is found to be advantageous both for its better approximation of the slope of the blackening curve and providing a clear physical meaning of all the parameters involved in this equation.