The special character of indigo-dyed yarns offers garment finishers many opportunities to enhance basic denim. One way is through wet processing, which encompasses two techniques: garment washing and garment wet finishing. Among other techniques, garment wet processing includes desizing, enzyme treatments, overdyeing, tinting, stonewashing, resin finishing, and softening.
Denim jeans must be desized to remove the sizing compounds that are applied to the indigo warp yarns prior to weaving. Many consumers prefer darker denim shades that have not been washed down severely. Rinse washes, such as dark rinse, use a chemical rinse to soften the fabric and fix the color.
Abrasive Color Loss
Stonewashing is a technique to accelerate the fading and softening of denim jeans by adding pumice stones to the wash. The stones can be natural or synthetic, in various sizes or shapes, to produce varied effects. The natural pumice stones used in stone washing are mined and produced in various grades. Stonewashing can be combined with other wet finishing steps, such as desizing and enzyme washing. Other abrasive techniques include the use of perlite and diatomaceous earth.
Discharge washing is a chemical technique that removes color from selected areas of dyed fabric. The chemistries used for discharge washing are either strong oxidizers, like potassium permanganate, or reducing agents, like sodium hypochlorite. Ozone processes, which are new to the industry, may offer a clean and simple method for color discharge. Another new technique involves the use of laccase enzyme. Some popular effects achieved by wet discharge include acid wash, moon wash, fog wash, marble wash, ice wash, frosted, snow wash, electric wash, and galactic wash.
Another type of wet finishing is chemical finishing, which includes such processes as softening, resin finishing, tinting, and overdyeing. Some of these processes require only tumble drying, while others require a curing step.