Traditionally, jeans

Traditionally, jeans

Traditionally, jeans were dyed to a blue color using natural indigo dye. Most denim is now dyed using synthetic indigo. Approximately 20 thousand tons of indigo are produced annually for this purpose, though only a few grams of the dye are required for each pair.^[23] For other colors of denim other dyes must be used. Currently, jeans are produced in any color that can be achieved with cotton.

For more information on dyeing, refer to denim and the discussion there of using pigment dyesTraditionally, jeans.