Stone washing

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.

[5] It is commonly accepted that French stylists Marithé + François Girbaud are inventors of industrialization of stone washing ("Stonewash" technique).

[10][11] 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.

[16] American Garment Finishers used a new cellulolytic agent patented in 1991 by Novo Nordisk from Denmark[17] because of its safer effect on cotton fiber.

Other finishers used an acid side Trichoderma fungi enzyme, cheaper and faster acting, but resulting in excessive fabric tear and a back lash because jeans pockets were lifting off.

California surfers and members of the 1960s counterculture prized Levi 501s and other jeans that had been bleached by the salt water due to their authentic, "lived in" appearance.

[20] During the early 1980s, skinheads and punk rockers would spatter bleach on their jeans and battle jackets for a mottled effect similar to camouflage.

[21] This early faded look, known as snow wash, tended to retain the original dark blue dye around the seams and waistband.

American Garment Finishers (AGF) from Texas industrialized the process in North America in June 1986 and offered it to Levi Strauss.

[25] Shortly afterward, AGF improved the technique by using potassium permanganate instead of bleach, achieving a more natural abraded look that is far less damaging to the cotton fibers.

Specific areas of the jeans, shirts and jackets were also acid-washed by spraying a solution of bleach or potassium permanganate to simulate a wear pattern.

Snow washed jeans, which retained more of the original blue dye, remained popular among grunge fans during the mid 1990s, until they were eventually supplanted by darker shades of denim associated with hardcore punk and hip hop fashion.