Study On Objective Evaluation Method Of Color Depth Based On Spectrophotometric Measurement

Color depth, which is one of the most common indicators used by colorist, is the basis to the evaluation of the color fastness and the dying properties. It affects the economic value of the dyestuff directly. Color depth is a complex indicator that is affected by hue, saturation and chroma. The subjective evaluation of color depth is prone to be influenced by people and environment, which is not easy to quantify. Since the 1950’s, scholars have put forward several objective evaluation formulas for color depth. These formulas play an important role in different areas. Each of them has its advantages and disadvantages. However, it is the lack of a unified, recognized objective evaluation formula.To objective understanding of these formulas and further research needs, this paper chooses 11 main objective evaluation formulas of color depth and the development and application situation are introduced firstly, and then investigated the effective of these color depth formulas through experiment method and theoretical analysis by Matlab. Results show that the effect of 8/11 formulas is relatively good, ranking the first is Godlove formula which is first proposed an experience formula, and has not been accepted generally and used widely.Two new color depth formulas Yang1 and Yang2 were put forward according to the definition of color depth through the spectral reflectance using high precision spectrophotometric measurement. The two formulas were inspected by SDC Standard Depth Scales and XYP equi-depth chipsby comparison with main color depth formulas. Results show that formula Yang2 performs the better than other 11 depth levels of chips.In order to check formula Yang2 furtherly, more equi-depth chips Scales are picked up by the ISO formula and the Gall formula in Munsell Color Space, the outcome indicate that Yang2 formula is better than other common color depth objective evaluation formula, but a few color depth, including Yang2 the same as other formulas calculated value near the yellow, have exceptions. The specific reason still needs to be investigated in the further study. Further application of inspection, improvement and optimization of the Yang2 formula will be done to propose a more accurate and universal color depth formula based on the theory of objective evaluation.