Color Fastness Assessment of Powdered Natural Dyestuffs under Accelerated Aging

In the analysis of dyeing cultural heritage, Color is one of the factors used for estimating dyestuffs, and dyestuff color changes due to aging must be examined. This study analyzed the degradation characteristics of powdered natural dyestuffs using a spectrophotometer. The dyestuffs used in the assessment to color fastness experiment included Sappan wood for red dyeing, Amur cork tree for yellow dyeing, indigo for blue dyeing, cupules of acorns for brown dyeing, and gallnuts for black dyeing. The powdered dyestuffs were subjected to ultraviolet(UV) irradiation as well as dry thermal, and wet thermal accelerated aging. Dyestuff powder pellets were prepared to measure color changes before and after accelerated aging. Results of dyestuff pellet color analysis showed that the Sappan wood exhibited the best color fastness under UV irradiation and the worst under dry thermal aging. Similarly, Amur cork, acorn cupule, and gallnut dyestuffs displayed good color fastness under UV irradiation but poor color fastness under wet thermal aging. By contrast, indigo dyestuff exhibited excellent color fastness under all aging conditions.