The Weft: The Half of Your Jeans You Never See
The Weft: The Half of Your Jeans You Never See
Flip your cuff. That pale thread decides more than you think.
Two Sets of Yarn
All woven cloth is two sets of yarn crossing at ninety degrees. The warp runs the length of the fabric and is held under tension on the loom. The weft runs across it, over and under, back and forth.
An easy way to keep them straight. The A in warp stands up and down like a warp yarn. The E in weft lies across like a weft yarn. Once you have that you never lose it.
Why Denim Looks Like Denim
Denim is a twill, which means the crossings step over by one each pass and produce a diagonal line on the surface. Classic denim is a three by one twill: three warp yarns showing on the face for every weft yarn. That makes it warp faced, which is why the front is dark blue and the back is pale.
The direction of that diagonal has a name and a consequence. Right hand twill runs from lower left toward upper right and is the most common. Left hand twill runs the other way, and it tends to soften faster and fade with a flatter, more vertical character. Broken twill alternates directions to stop the fabric pulling and to prevent leg twist, which is that annoying spiral you see in cheap jeans after a few washes.
The Weft Is Where the Secret Lives
The warp is dyed indigo. The weft is left undyed. Originally that was economy. You could only see the weft when the cloth was turned over, so why pay to dye it.
That accident is the reason denim is the most beautiful aging fabric in clothing. Every fade you have ever admired is white weft and white yarn core coming up through blue warp. If both sets were dyed, which is what double indigo means, the whole thing would age quietly and evenly and nobody would collect jeans.
The weft does other work too. Its weight and yarn count set the hand of the cloth: how it drapes, how stiff it starts, how it breaks in. Put a slub yarn in the weft, spun deliberately uneven, and you get texture running across the fabric that shows up as character from the very first wear.
The Shuttle and the Self Edge
On a shuttle loom, a wooden shuttle carries one continuous weft yarn back and forth across a narrow warp. Because the same yarn turns around at each side, it binds the edge closed. That bound edge is the selvedge, the self edge, and it is not a decoration. It is evidence of how the cloth was made.
Shuttle looms appeared in England in 1785. Sakichi Toyoda developed the automatic version in Japan in 1897, and those Japanese looms are the ancestors of most of the selvedge denim being woven today. Modern projectile looms shoot a fresh length of weft across a much wider warp at far greater speed, and leave a frayed edge instead of a bound one. They are not bad looms. They are fast looms, and speed and character pull in opposite directions.
What Ours Is
Our main cloth is a 13.5 ounce shuttle loom woven selvedge denim, produced specially for us in Japan and sanforized so that the size you buy is the size you keep.
The gen-2 ONE Jean Jacket runs a heavier 14 ounce selvedge, rope dyed, seven by six point eight yarn, with very high warp density. High warp density means more indigo threads packed into the same space, which gives a deeper starting color and a slower, sharper fade. It is stitched triple needle throughout with bright gold thread, our donut button, and a diamond back stitch on the collar.
Details like that are why I go there. A mill and a sewing room in Okayama that have been at this for generations will hold a warp density spec. Somebody else will tell you it does not matter.
Turn your cuff back and look at the pale thread. That is the part of the jacket nobody photographs, and it is the reason the photographs look good in ten years.
A Way Of Life.
Shop the Story
The Black Bear Brand ONE Jean Jacket, gen-2
The Black Bear Brand ONE Jean Vest
The Black Bear Brand ONE Jeans
Related Reading
Selvedge Denim, Explained: The Self-Edge, the Sanforized Fit, and the Story in Every Fade
The Old American Machines in Japan: The Myth, the Truth, and Why the Craft Lives There