Sustainable dyeing of Eri silk fabric with “Rubia cordifolia”: process optimization and effect of alum and myrobalan mordants

Abstract

Among the genus Rubia's most important and practical species in the Indian subcontinent is Rubia cordifolia Linnae, which has very long, cylindrical, flexuous roots with thin red bark. This plant's most valuable component “entire root”, which is quite long but not much thicker is considered as the most valuable portion (Yusuf et al., 2017)¹.Natural dye “Rubia cordifolia”, Eri Silk fabric, mordant myrobalan and alum, were selected for the study. The highest K/S value 16.26 was given by myrobalan mordanted fabric, and a greater depth of colour was given by the non-mordanted fabric. Additionally, it was observed that because of various mordants, the dyed samples varied from one another. Compared to alum-mordanted fabric, myrobalanmordanted fabric has a smooth, uniform surface (Sarma, P.et al.,2025)². This paper describes how Eri silk fabric is dyed using natural dyes extracted from Rubia cordifolia. The mordants used were alum and myrobalan. The colourfastness properties and colour co-ordinates of dyed fabrics were evaluated and the fabric samples showed very fair to good ratings of colourfastness with slightly stained to no staining (Kaswan, S., et al., 2025)³.