Selvage denim is made on old-style shuttle looms. The fabric is woven using one continuous cross thread; the weft. As the weft loops back into the edge of the weave, the selvage edge is created. This edge is usually stitched with a colored thread. On vintage jeans, some selvage denim has green, brown, or yellow thread running down the edge. These stitches were intended as distinctions used by the mills to differentiate between fabrics. Best known is the red selvage.
Selvage production is much slower than conventionally produced denim, and only the best raw materials are used. It can be compared to the “slow food” movement; this is slow denim.
The old shuttle looms produce three meters of 75 centimeter-wide selvage denim per hour, and a modern loom is more than ten times faster. And, as the shuttle looms date back to the 1950s, they require a lot of tender loving care in order to work.
Modern denim production is a high-tech industry in which computers control much of the process. In the slow denim factory, the looms are under constant supervision from a couple of denim craftsmen, who oil the machinery and inspect the weaves.
The rhythmic sound of the shuttles going back and forth creates a loud and hypnotic soundtrack. Naturally, the slow production process makes the denim more expensive, but there are also many advantages. The low speed produces far less stress on the yarn, which makes the hand of the denim softer and the fabric more durable.