Use of characteristics of modern photographic materials in spectral determination of trace elements

The variation of detection limit has been investigated and the contrast and information sensitivity of the photographic materials used as a criterion for assessing the improvement of spectral analysis. The detection limits are lowered (a) when a more suitable type of plate is used, and (b) when the exposure time is increased. Both factors allow an optimum value for the contrast sensitivity to be reached. No improvement of the detection limits was observed when a continuous spectrum was recorded on top of the studied spectra. This superimposition of spectra was used for obtaining the information sensitivity value. The contrast sensitivity, but not the information sensitivity, can be used to predict changes in detection limits.