Cr³⁺ Effect on the Correlation between Lightness Difference and Color Difference of Ruby Red

Abstract:

The correlations between of lightness, chroma, Cr3+ and color index were studied to analyze the impact of all these three elements on ruby red color; and with the color difference research, the lightness difference is testified to be the key affecting color appearance. Based on the uniform color space CIE 1976L*a*b*, the ruby displays the best red color when the content of Cr3+ is within (1555, 5183ppm), L* (32.64, 44.25) and ho  (354.14, 0.7). With the help of partial correlation analysis of color difference, it is illustrated that the correlation between L* and E* (r=0.999) is relatively higher than that between L* and E* (r=0.948); and with high significance level ( = 0.129) of H* and E*, it shows that H* has little impact on E*. It is concluded that the color change of ruby from red to purple are mostly affected by lightness change; lightness difference should be considered as the most important factor when evaluating the red color of ruby, and then followed by the chroma and hue jointly.

• Periodical: Advanced Materials Research (Volume 177)
• Pages: 624-627
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.177.624
• Online since: December 2010
• Authors: Ying Guo, Xiang Li, Li Tian
• Keywords: Color Evaluation, Color-Difference, Cr³⁺, Ruby

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