Denim
A rugged warp-faced cotton twill with a coloured warp and white weft — the fabric of jeans.
Also known as: Jean cloth
beginner Named from serge de Nîmes, France
Denim is a heavy cotton twill woven so the indigo-dyed warp dominates the face and the undyed weft shows on the back, giving its two-tone look and characteristic fade.
What it is
Denim is a warp-faced 3/1 twill, most often 100% cotton, in which an indigo-dyed warp passes over three weft yarns before going under one. Because indigo dyes only the surface of the yarn (ring-dyeing), denim fades as the outer colour wears away, revealing the white core — the effect prized in worn jeans. The undyed weft is why the reverse of denim looks pale.
Weight is quoted in ounces per square yard, typically 8–16 oz (roughly 270–540 GSM); 12–14 oz is standard for jeans. Raw (unwashed) denim develops personalised fade lines, while selvedge denim is woven on narrow shuttle looms leaving a clean self-finished edge. Stretch denim adds a few per cent elastane for comfort. Heavier weights are stiffer and more durable; lighter weights suit shirts and dresses.
Worked example
A classic pair of Levi's-style five-pocket jeans uses roughly 12–14 oz right-hand 3/1 indigo cotton twill; selvedge purists favour narrow-loom cloth with the coloured self-edge visible in the cuff.
Failure mode — when it misleads
Unwashed raw denim shrinks 5–10% and crocks (rubs off indigo) onto light surfaces; sanforised or pre-washed denim avoids the surprise shrink.
How to apply it
Pick 12–14 oz for durable jeans, lighter 8–10 oz for shirts and dresses, and add 1–2% elastane where a comfort stretch is wanted.
Related entries
Sources & further reading
- Denim: Fashion's Frontier — Emma McClendon (book)