UC Davis

Color depth is difficult to evaluate; however, it plays an important role in the assessments of color fastness, dyeing properties, and so on. The subjective evaluation of color depth is prone to be affected by people, environment, etc. As for objective evaluation, there are more than 10 formulas, which confuses the user. In this study, a theoretically designed new formula is inspected through 18195 chips with 24 grades of color depth from the SINO COLOR BOOK, with the help of four preferable objective evaluation formulas. The specimens were measured using an X-Rite Color i7 spectrophotometer, and all their depth values were calculated and statistically analyzed by programming MATLAB. Of the five formulas, the new formula yields the best outcome of variance coefficients (CVs) but the worst linearity, with a correlation coefficient R = 0.976. It was then theoretically revised to two other formulas, one obtains the highest linearity (R = 0.9997) and the third CV, and the other gains the second linearity (R = 0.9984) and the second CV among the seven formulas. Besides, the three new formulas are not as sensitive as the others to the changes of Hue and Chroma. In general, the new revised formulas show potential and need to be further evaluated.