Greige fabric, straight off the circular machine, has a different GSM, width and hand from finished fabric because it goes through wet and heat processes that relax it. Yarns are under tension during knitting; in washing, dyeing and drying they move back toward equilibrium, so the fabric shortens in length and changes in width. GSM usually rises after relaxation. Finishes such as softener, compacting and brushing then change the hand and dimensional stability. That is why GSM, width and shrinkage should always be specified on the finished fabric, never on the greige.
greigefinishingrelaxation
