Indigo: The Oldest Blue, and Why It Fades Like Nothing Else
Indigo: The Oldest Blue, and Why It Fades Like Nothing Else
The only dye that leaves on purpose.
1,400 Years of Blue
Indigo reached Japan along the Silk Road roughly fourteen hundred years ago. It went first to the Heian court, where it was a color for aristocrats. From the twelfth century the warrior class took it up, and not for looks. Indigo makes cloth stronger. It repels insects. It has antibacterial properties. Armor padding and undergarments went blue for reasons a quartermaster would approve.
Then cotton cultivation spread in the Edo period, and cotton takes indigo easily. Farmers wore it. Laborers wore it. Shops dyed their door curtains with it. When the British chemist R. W. Atkinson visited in the 1870s, he saw so much of it that he called the color Japan Blue, and the name stuck.
The best of it came from Tokushima, historically Awa province, where the trade made a region wealthy. The leaves are sun dried and then fermented for months into a compost called sukumo, which becomes the base of the vat. It takes about a year of work to get a usable blue out of a plant with green leaves. In Okayama, where our denim is woven, indigo dyeing can be traced back to the 1600s.
Why It Fades and Nothing Else Does
Here is the mechanism, and it is the most important fact in denim.
Most dyes penetrate a fiber. Indigo does not. It bonds to the outside of the yarn and leaves a white cotton core untouched. Cut a rope dyed yarn in half and you see a blue ring around a pale center.
That is the whole secret. When you wear jeans, friction removes the outer blue and exposes the white underneath. Your knees, your thighs, your wallet, the way you sit and ride and bend all take dye off at different rates. What comes out is not damage. It is a record.
Rope Dyeing, and Why Japan Kept It
To rope dye, the warp yarn is twisted into thick ropes and dipped into indigo vats repeatedly, often six to sixteen times, with oxidation between dips. Each pass lays down another shell of color. The short contact time is deliberate. It keeps the dye on the surface where it can be worn away.
American and European mills largely moved to slasher dyeing, pulling flat sheets of warp through one long bath. It is faster and more even, and it drives dye deeper into the yarn. You get a very dark jean that will not fade dramatically.
Japanese mills stayed with rope dyeing, because Japanese mills were chasing the fades. Kojima in Okayama had every piece of the puzzle already: cotton, centuries of indigo knowledge, and sewing rooms with heavy cloth experience. Japan's first domestically made jeans came out of that town in the mid 1960s, and within a decade the mills there were making their own indigo denim rather than importing it.
What This Means When You Buy Jeans
Look at the inside of the cuff. If it is pale, the weft is undyed and the warp is doing the work. That is normal denim and it will fade blue over white. If both sides are blue, that is double indigo and it will fade differently and more slowly.
Expect dye transfer at the beginning. New indigo will mark a white sofa, a light shirt and the inside of a pale boot. It settles down.
Then wear them. A pair of raw jeans is the only thing in your wardrobe that gets more valuable the harder you use it.
Ours are 13.5 ounce shuttle loom woven selvedge, produced specially for us in Japan, and sanforized so the fit you buy stays the fit you have. The Vintage Ultimate Jeans are built on botanical indigo and rope dyed organic cotton, which is as close to the old vats as a modern jean gets.
A Way Of Life.
Shop the Story
The Black Bear Brand ONE Jeans
The Black Bear Brand double front Jeans
Black Bear Brand Indigo Cowboy Jeans
Vintage BLACK BEAR BRAND, The Ultimate Jeans in botanical indigo
Related Reading
Botanical Indigo: The Oldest Blue, and the Jeans I Built Around It
Selvedge Denim, Explained: The Self-Edge, the Sanforized Fit, and the Story in Every Fade