Of all the defects a dyehouse meets, the streak is the one that starts the most arguments. The customer sees a dark or pale line running down the fabric and concludes that the dyehouse did not dye it evenly. In most cases the trace was already in the material — in the yarn, on the loom or knitting machine, in the pretreatment bath — long before the fabric reached the dye vessel.
The dye vessel behaves like a developer. Differences that were invisible in greige are pushed into visible bands by dye, heat and tension. With the same lot of greige, a gentle process leaves no streak; an aggressive process makes it jump out. Solving streaking therefore cannot start and end at the dyeing step. It has to be intercepted along the chain: yarn, fabric, pretreatment, dyeing — one level at a time.