The Effect Of Color Rending Property Of Light Source On The Evaluation Of Green Jade

From perspective of light to explain how light sources affect the evaluation of green jade. It calculates (D65,A) two lights'color rending indexs. It tests and summarys the jades'color parameters characteristics on the condition of three different lights(D65,CWF,A).It explains the phenomenon of metamerism caused by light changes. In order to study the relationship between color parameters and the color difference, mathematical analysis of variance and cluster analysis are used.In this thesis, two light sources'(D65,A) spectral power distribution are measured by PR715 spectral radiometer. In accordance with GB/T 5702-2003, it calculates the D65 and A light sources'color rendering index, respectively,80.02,92.39. The different spectrum power distribution between D65,A and the standard lightings'is the main reason why D65's and A's color rending index less than 100.It measures 277 jades'color parameters in three light sources (D65,CWF,A) by spectrophotometer. In D65, jades appear the highest L*.The sorting of a* from small to large is D65,A,CWF. Therefore, in order to make the green jades show perfect color, the selecting light order will be D65,A,CWF.In D65, it selects three groups of jades, every group's jades have tiny color difference. It found that their metamerism index are mainly related with light sources'spectral power distribution and their reflect curves. The light source determines which part of the spectral that jade can absorb or reflect. The similar of the two jades's reflectant curve, the less color change when changing light sources.Two factor variance analysis shows that both the light source and the jade itself have great impact on the color of jade. Single factor analysis of variance shows that changing light has less impact on the L* of jade, while, it has great impact on the other color parameters.It picks up some Jades with similar green color, their color variables and their metamerism indexs are clustered, shows that L* has the biggest effect on two jades'metamerism, followed by b*, a*, which provides some basis for general calculation of metamerism indexs.