What is Selvedge Denim?
Before we answer that, let’s back up and make a few general distinctions about fabric. First, clothing fabric is made on a weaving machine or a loom. Second, most clothing fabrics are made up of two parts - warp yarns (that run vertically or up-and-down) and weft yarns (which run horizontally or left to right). Denim is a typical clothing fabric in that it uses a warp and weft and is made on a loom.
Looms weave fabric by holding the warp yarns in place while the weft passes between them. But how they pass through the weft is illustrative of the type of loom and the fabric that it creates at the end of the process. Prior to WWII much of the fabric that was produced (and nearly all the denim) was made on Shuttle Looms. A shuttle loom uses a shuttle to pass the weft back and forth, looping on the end of the fabric. This loop as the shuttle changes direction creates a finished or self-edge in the fabric.
The term for this finished edge was called a selvedge (self-edge, selvage, salvage). It was a benefit of the fabric in that it didn’t need to be bound to prevent fraying or unraveling. And as most shuttle looms created fabric about a yard wide it allowed for an efficient layout for a pair of jeans - perfectly lining up the outside leg of the jean with the selvedge. This stripe of finished edge allowed mills and the manufacturers using the fabric to come up with identification colors, Levis became known for it’s single red stripe ticker, Lee had a green stripe on some of it’s fabric and Wrangler used a yellow stripe on some of it’s denim.
This all changed after the War and the demand for denim increased. Most mills then looked to more efficient technology such as the projectile loom which produced nearly 15 times as much fabric as a shuttle loom. One of the downsides though was that on these modern looms, the weft yarn is cut on every pass creating a fringe on the edge that needs a stitch to prevent the fabric from fraying - thus loosing that finished edge and colored stripe.
There are still mills that use the old shuttle looms though and they continue to produce selvedge fabric. For the most part, this selvedge denim is valued for it’s quality, it’s character and sometimes the interesting irregularities in the fabric. We’ll talk more about the differences of selvedge vs modern denim at a later date as there are many factors to consider when you think about your next pair of jeans. But hopefully this bit of background will help in your decision making.