Fibre · Warp faced twill, indigo dyed
Denim
A cotton twill whose entire character comes from a dye that never penetrates the yarn and wears off exactly where you move.
Why indigo behaves the way it does
Indigo is not soluble in water in its dyed form, so it is applied in a reduced state and then oxidised on the yarn. It bonds to the surface of the cotton fibre and does not penetrate the core, which is why a denim yarn cut in half is white in the middle. Every abrasion removes a layer of surface dye and exposes the white core underneath, which is the entire mechanism of fading.
It means the fade pattern is a record of movement. The creases behind the knee, the line of a wallet, the fade at the thigh where a hand rests. This is either the most interesting property of any garment in common use or a reason to buy something else, and the market has been arguing about it since the 1980s.
Selvedge, which is a loom and not a quality
Selvedge denim is woven on an old shuttle loom, which produces a narrow bolt with a self finished edge that does not fray. The looms are slow, the cloth is narrow, and a pair of jeans is cut so that the finished edge runs down the outseam. It is a genuine mark of a particular production method and it correlates loosely with care taken elsewhere, but the cloth is not stronger for being selvedge. A wide loom denim from a good mill can be a better cloth.
Raw, and the washing argument
Raw denim is unwashed after dyeing, stiff, dark, and shrinks substantially at the first wash unless it has been sanforized. The advice never to wash it is folklore that damages trousers: dirt and body salt abrade cotton fibres, and a pair worn for a year unwashed is wearing out faster than one washed every two months. Cold, inside out, hung to dry, every six to eight weeks of regular wear. The fades will be slightly softer and the trousers will last twice as long.
Weight, in ounces
Heavier is not better, it is a different garment with a different break in period.
How to check it
- Turn out the hem. A selvedge edge is a clean self finished line, usually with a coloured thread running through it.
- Check the weight. If it is not stated, the cloth is probably nothing special.
- Look at the pocket bags. Heavy cotton drill lasts, thin polycotton wears through in a year and is the most common first failure.
- Check for a small amount of elastane if comfort matters more than fade. One to two per cent changes the wear enormously and rules out the classic fade pattern.
Care
- Wash cold, inside out, every six to eight weeks of regular wear.
- Hang to dry. A tumble dryer is what shrinks and distorts denim, not the wash.
- Repair at the first sign of thinning. A darn at the crotch costs very little and a hole there costs the trousers.
- Never iron a crease into denim. The dye at the crease abrades faster and the line becomes permanent.