This paper investigates the feasibility of dyeing viscose rayon fabric with an
anthocyanin solution extracted from H. sabdariffa L. calyces. For eco-friendly
dyeing and improvement of the natural dye’s affinity to fabrics, natural
mordants instead of traditional metallic mordants were applied. The effect
of natural mordant types and mordanting procedures (pre-, meta- and aftermordanting) was evaluated by colorimetric measurement (CIE Lab and K/S
values) and color fastness. Four natural mordants including alginate, walnut
hull, lemon peel, and pinecone were used. The results show that the light and
wash fastness (1–2 degrees according to the blue scale and the grayscale) of
the un-mordanted viscose fabric were very low and unsuitable. Natural
mordants, especially walnut husk and alginate, could improve color strength
and color fastness. The light fastness value of the dyed fabric was improved,
reaching a value of 5–6 in the presence of walnut, lemon, and pinecone
mordants. The highest wash and light fastness was obtained when the aftermordanting method was used. Also, the use of walnut husk mordant
increased the color strength and decreased the lightness of the dyed fabrics,
as compared to other natural mordants, in all three methods of mordanting