Acid wash

Stone washing is a textile manufacturing process used to give a newly manufactured cloth garment a worn-in (or worn-out) appearance. Stone-washing also helps to increase the softness and flexibility of otherwise stiff and rigid fabrics such as canvas and denim.

The process uses large stones to roughen up the fabric being processed. The garments are placed in a large horizontal industrial clothes washer that is also filled with large stones. As the wash cylinder rotates, the cloth fibers are repeatedly pounded and beaten as the tumbling stones ride up the paddles inside the drum and fall back down onto the fabric.

A number of people and organizations have claimed to have invented stone-washing. According to Levi Strauss & Co., Donald Freeland, an employee of the Great Western Garment Company (later acquired by Levi's), invented "stone-washing" denim in the 1950s. Inventor Claude Blankiet has also been credited with having invented the technique in the 1970s. The jeans company Edwin claims to have invented the technique in the 1980s.

Stonewashed jeans are jeans that have been treated to produce a faded, worn appearance. This is usually accomplished either by washing the jeans with pumice in a rotating drum, or also by using chemicals to create the appearance without the use of a rotating drum. The expanding cost of importing pumice stone from Italy, Greece and Turkey led to extensive mining of pumice deposits in California, Arizona, and New Mexico, triggering a negative response from American ecologist groups. The reduction of pumice usage and the growing disposal of its chemically-tainted residue triggered a search for novel methods, notably the use of alternative abrading materials or machines and the use of cellulase enzymes. Stonewashed jeans were a popular 1970s fashion trend, before commercial acid wash denim (discussed below) was introduced in the 1980s. In the 2000s, stonewashed jeans were heavily distressed, with pre-made holes, frayed edges and extensive fading caused by sandblasting.

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