When denim’s popularity skyrocketed after World War II, most manufacturers started using projectile looms. The weave is the same but individual weft threads are shot through the warp by bullet shaped projectiles.

This is how you get the frayed edges you see on the sides of most denim. Among the advantages of these looms are: fabric could be made in 60” or even 108” widths instead of 36”, they required less maintenance and human oversight, and they produced very uniform fabric that was less expensive.

Most US companies sold their shuttle looms to overseas manufacturers, especially the Japanese, who welcomed the looms to satisfy their domestic clamor for jeans.

Like most things, selvedge denim has made a comeback. It is now highly prized. Although the weave is more densely packed than projectile denim, the fabric is still softer and more flexible. The finished edges with their colored thread stripe is a badge of quality.

Needless to say, the Japanese have some of the most highly prized selvedge denim, although Turkey, Bangladesh, Italy and the US also produce high-quality selvedge denim.

In fact, Cone Mill, in Greensboro, North Carolina was the original producer of denim for Levi’s and still makes their selvedge denim with a red stripe for 501 jeans.

If you are shopping for vintage jeans, the colored thread at the edge can help you identify the manufacturer of the denim, and even, perhaps, whether the item is authentic.

Historically, mills would produce denim for different jeans manufacturers. To differentiate the orders, they would use a different colored thread. For instance, vintage Lee jeans should have a blue or green stripe (depending on the style) and Wrangler’s should have a yellow thread.

The denim was all made by Cone Mill’s White Oak Plant. So, if you see something labeled as vintage Wrangler’s but there is a red stripe, you know you are looking at a counterfeit.