The measurement of radiant energy by the photographic plate has given an enormous advantage to the spectroscopy.
It can simultaneously and permanently reccrd a wide region of wave length with an unexcelled power of discrimination and this characteristic is a indispensable factor for the quantitative spectrographic analysis which requires the determination of intensity ratio of several spectral lines based on the simultaneity of emission source.
In spite of these excellent characteristics, however, owing to its property of reciprocity failure, the spectrochemical analyst frequently has to reinvestigate about the photometry in order to establish their applicability for his work.
To avoid such troubles the authors have contrived a new quantitative method which maked good use of this failure. And from the standpoint of variation for analytical substances and of less time-consuming, the authors have attempted an another method using a two-stepped filter.
The outline of these theories and prccedures is reported here.