The Study On Influencing Factors Of Predicting Ruby Color Appearance

This paper, by using CIECAM02color appearance model, is to study the feasibility and ability of forecasting ruby color appearance parameters whiletransformatingtheconditions of surround environment,standard light and the intensity ofillumination. Compared with the CIE1976L*a*b*color parameters(lightness chroma, hue), the difference between the two models is analyzed. In order to find the appropriatecolorimetric systems to value ruby color, the uniform color space Munsell system is used for proving uniformity of CIELAB color space and CIECAM02color model.Use Color i5color measurement instrument measuring red rubytristimulus values (XYZ) and CIE1976L*a*b*chromaticity parameters L*,a*b*. The ruby color appearanceparameters is calculated by CIECAM02color model, under different surround(Average, Dim, Dark), standard light(D65、A) and the intensity ofillumination of D65.CIECAM02can successfully predict the ruby complex color appearance phenomena, like the visual color balance, the Hunt effect, the Stevens effect and the Helson-Judd effect.Statistical results show that the influence degree of surround is brightness (r=0.869) saturation (r=0.763)> lightness (r=-0.556)> chroma (r=-0.352), the influence degree of intensity ofillumination is brightness(r=0.648)> colorfulness (r=0.259)> saturation (r=-0.231).Compared with Munsell system, the results indicate:1.CIECAM02color model has relatively low lightness (Average ΔL=8.93), but CIECAM02and CIELAB model have a similar result aspect of lightness(R2V×J=R2V×L=0.999).2. CIELAB is preferable than CIECAM02on predicting low chroma ruby, the difference is getting smaller when the ruby chroma is higher.3. There is a bigger angle difference between hue angle calculated by Munsell system and calculated by CIECAM02model when the hue is RP, while hue angle of CIECAM02is also bigger than CIELAB’s.As a result, using CIE1976L*a*b*color space is available if only a brief description and evaluation of ruby color with lightness, chroma and hue. If other complicated practical problems are considered, it is recommended to use the CIECAM02color appearance model.