A Study on Over-dyeing Techniques and Chromatic Expansion of Yellow Plant Dyes for Sustainable Fashion

Abstract

The limited color range of single plant dyes significantly restricts their application in sustainable fashion. This study proposes a strategy using Phellodendron amurense Rupr. (Amur cork tree) as a base, combined with over-dyeing techniques involving four other yellow dyes—Gardenia jasminoides J. Ellis (Gardenia), Curcuma longa L. (Turmeric), Punica granatum L. (Pomegranate peel), and Cotinus coggygria var. cinereus Engl. (Smoke tree). Through systematic colorimetric analysis (L*a*b*, K/S), we demonstrate that this technique effectively broadens the yellow spectrum by precisely adjusting hue and enhancing color depth. Key findings include the successful attainment of a bright, cool-toned lemon yellow; substantial improvement in the color performance of low-strength dyes such as Pomegranate peel; and the creation of deep, saturated neutral to warm yellow shades. Based on the resulting colors, this study further delineates specific application scenarios in sustainable fashion and confirms that process-optimized yellow plant dyes can supply a rich color diversity while facilitating a feasible transition for the industry toward environmentally sustainable practices.