Densitometry and Chromaticity: The Right Instrument for the Job

Densitometric and colorimetric techniques for the comparison of the color characteristic of an ink and paper solid have been compared. The measurement parameters used were the densitometer derived hue error and grayness and the CIE L*a*b* chromaticity values of hue angle and chroma. Statistical calculations have been derived from the relevant equipment manufacturers' specifications to indicate possible minimum specification limits for both of the techniques used based on instrument measurement noise. Densitometer analysis indicated that seven yellow inks were essentially the same. Colorimetric analysis indicated similarities and differences. Visual inspection is the final criterion. Visual inspection, under correct illumination, indicates better correlation to chromaticity measurements than densitometry between the ink samples. It is evident that the colorimeter values more closely match that of our visual determinations.