Photographic emulsions relative line intensities

Relative intensities of spectral lines, if they are accurately known, also can be used for photographic emulsion calibration. For this purpose, it is necessary that the relative spectral line intensities be well established and that they exhibit no self-absorption. The lines should have approximately the same excitation energies. The spectral lines should lie in the same general spectral region since emulsion contrast (emulsion gamma) varies with wavelength. 

Its value can be measured directly, but in photographic measurements it can be calculated from the standard deviation of the blackening with the aid of Equation (115). The latter shows that for trace analyses, emulsions with a high y must be used. In photoelectric measurements, 0 is the relative standard deviation of the background intensity, measured at a wavelength adjacent to the spectral line or in a blank sample at the wavelength of the analytical line. It may comprise several contributions ... 

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