文摘
Rubia cordifolia (Tamin, local name) produces anthraquinone reddish orange dyes in roots, stem and leaves, which has been used for dyeing textiles since ancient times. Commercial sonicator dyeing with Rubia showed that pretreatment with biomordant, Eurya acuminata DC var euprista Karth. (Theaceae family) [local name, Nausankhee (Apatani tribe), Turku (Nyishi tribe) in 2 % ] shows very good fastness properties for dyed cotton using dry powder as 10 % of the weight of the fabric is optimum. Use of biomordant replaces metal mordants making natural dyeing ecofriendly.