The compatibility rating of any two natural dyes applied together for obtaining compound shade has been determined. The natural dyes selected for compatibility study are, babool (BL), pomegranate rind (PR), madder or manjistha (MJ), red sandal wood (RSW), tesu flower (TF) and catechu (CT) based on their maximum commercial use. The dyes have been extracted in aqueous medium under optimized conditions and their binary mixtures in different proportions are used to dye cotton khadi fabric for developing varying compound shades on 15% overall concentration of myrobolan (harda) and aluminium sulphate (75:25) in sequence double pre-mordanted cotton khadi fabric. After dyeing with binary mixtures of natural dyes , dyed cotton fabric samples are subjected to evaluation of K/S, colour differences (∆E), colour difference index (CDI) values; changes in hue /chroma, brightness index (BI), metamerism index (MI) etc; and also colour fastness to washing, light, rubbing and perspiration. The compatibility of these binary pairs of natural dyes has been assessed conventionally (∆c vs ∆L and K/S vs ∆L), as well as using an unique and simple novel method of compatibility test applied for assessing relative compatibility rating (RCR) of each binary pairs of natural dyes, by evaluating colour difference index [(∆E x ∆H) / (∆C x MI)] for application of different proportion of two dyes in each binary pair. The results of this novel simple method are found mostly in well agreement with the findings of compatibility test by conventional methods. Finally, the order of relative degree of compatibility of these binary pairs of natural dyes is found to be BL: MJ > BL: RSW > BL: CT > BL: PR > BL: TF.

中文翻译：

---

天然染料二元混合物用于开发棉卡迪织物复合色调的相容性

任何两种天然染料一起使用以获得复合色调的相容性等级已经确定。选择用于相容性研究的天然染料是巴布尔 (BL)、石榴皮 (PR)、茜草或曼吉斯塔 (MJ)、紫檀木 (RSW)、特苏花 (TF) 和儿茶 (CT)，基于它们的最大商业用途. 在优化条件下在水性介质中提取染料，并使用不同比例的二元混合物对棉卡迪织物进行染色，以在 15% 总浓度的 myrobolan (harda) 和硫酸铝 (75:25) 上依次形成不同的复合色调双预媒染棉卡迪面料。用天然染料的二元混合物染色后，染色棉织物样品进行K/S、色差（ΔE）、色差指数（CDI）值的评估；色调/色度、亮度指数（BI）、同色异谱指数（MI）等的变化；以及耐水洗、耐光、耐摩擦和耐汗渍的色牢度。这些天然染料的二元对的兼容性已通过常规评估（Δc 与 ΔL 和 K/S 与 ΔL），并使用一种独特且简单的新型兼容性测试方法来评估相对兼容性等级 (RCR)通过评估色差指数 [(ΔE x ΔH) / (ΔC x MI)] 来计算每个二元对天然染料的不同比例的两种染料的应用。发现这种新颖的简单方法的结果与通过常规方法进行的相容性测试的结果基本一致。最后，发现这些天然染料二元对的相对相容性程度的顺序是BL：MJ>BL：RSW>BL：CT>BL：PR>