Feasibility Study On Color Evaluation Of Jadeite Based On Gem Dialogue

This paper focuses on the feasibility of GemDialogue used in the evaluation of green color of jadeite.Based on the CIE 1976 L*a*b* uniform color space,using SP60 CS X-rite portable colorimeter to measure GemDialogue color card,which contains G2 Y,Y2G,G,B2 G,G2B five cards.The illuminants conditions selected D65,F2,andA three different illuminants.The color parameters include L*,a*,b*,C*,h0 five items.As a gem colorimetrictool,GemDialogue has rich color samples and easy to carry,which is widely used in the world.It is also widely used in gem industry in China.GemDialogue itself can be used as a semi-quantitative test colorimetric tool,which has the advantage of scientific and efficient.Through analyzing variation,distribution characteristics and performance of the color card under the test light of the test data,analyzing the character of GemDialogue.Which would establish the theoretical basis for judging the color,choosing the ribbon,grading the ribbon and the use of colorimetric method in the quality evaluation process of jadeite green color.In all the test data,1435 data according to the color evaluation of jadeiteselected.L*,a* and b* were used as variables.The data was analyzed by SPSS19.0 software.K-Means rapid clustering analysis(ANOVA)of the three parameters of L*,a*and b* are smaller than the significance level of 0.01,which indicates that the seven categories division is successful.In addition,Fisher discriminant analysis verifies that the correct rate of data classification is 98% and the precision is ideal.seven color gradients in the color quality evaluation system were established,including vivid green,fancy green,green,deep green,dark green,light green and greyish-green.According to the color of the visual effects and commercial value,the first green color is the best quality,the seventhgreyish-greenis the worst.On this basis,the discriminant analysis of the establishment of the category judgment function can also make a quick evaluation to theunknown jadeitegreen color quality.This paper makes a complete test on the green part of GemDialogue.The database after screeningis only for the quality evaluation of jadeite green color.The data screening can be based on the color characteristics of different green gems to establish different database of green gems,Based on the method of jadeite green color quality evaluation,the color quality evaluation system suitable for other green gemstones can be derived.