Stone wash

Stone washing emerged in the 1950s — according to Levi Strauss & Co., Donald Freeland at Great Western Garment Company invented the process. Marithé + François Girbaud industrialised it in the 1970s, Rifle Jeans patented it in 1986. The process runs in large drum washers: denim pieces are tumbled with pumice stones (from Italy, Greece, Turkey) for 30-90 minutes.

The stones rub the indigo out of the outer layers of the warp fibres (ring dyeing) and create the characteristic thread-by-thread blue-grey look with light stretched areas on seams and edges. At the same time the fibres are mechanically broken, making the hand feel noticeably softer and the fit wearable from the shelf.

Ecologically problematic: high pumice mining in Mediterranean and volcanic regions, high water use to flush out stone debris, short lifespan of treated jeans. Modern alternative is enzyme washing (biostoning) with cellulase enzymes achieving the same effect with much less water and no stone mining.