Emission spectral analysis using photographic plates treated with a phenidone developer

When spectral photographic plates are not treated in the conventional metol-hydroquinone developer, but in a phenidone developer, a strong increase in the sensitivity and a certain increase in the contrast are observed. With phenidone development, weak lines are intensified, permitting the lowering of the limits of detection and determination. The increase in the contrast increases the slope of the concentration-calibration curves and hence the concentrational sensitivity of the spectral analyses. This is illustrated in the curves for the determination of Si and Mn in low-alloy steels. Further sensitivity can be obtained by following the phenidone development by a chromium intensifying process.