Effect of cotton fiber and yarn characteristics on color variation in woven fabric dyed with vat dyes

The aim of this study was to investigate the effect of cotton fiber and yarn characteristics on the color variation of woven fabrics dyed with vat dyes. A fabric length of 31?m was woven so that each meter of the fabric comprised weft yarns of slightly different cotton fiber or yarn characteristics as compared to the other. The woven fabric was pretreated and dyed with vat dyes using industrial-scale, pad-dry-chemical-pad-steam process. After dyeing it was found that the fabric containing weft yarns made from cotton with higher reflectance (Rd) values gave poor color strength as compared to that of lower Rd values. Fabric comprising combed weft yarns showed better color depth (K/S) values as compared to that comprising carded weft yarns made from the same raw cotton. Furthermore, the fabric comprising finer- or lower-twist weft yarns gave higher color depth as compared to that with coarser or higher-twist weft yarns. It was concluded that slight variations in the cotton or yarn characteristics in the weft yarns could result in significant shade variations in the vat-dyed fabric.