Denim is available in a range of colors, but the most common denim is indigo denim in which the warp thread is dyed while the weft thread is left white. As a result of the warp-faced twill weaving, one side of the textile is dominated by the blue warp threads and the other side is dominated by the white weft threads. Jeans fabricated from this cloth are thus predominantly white on the inside.Denim is a sturdy cotton warp-faced textile in which the weft passes under two or more warp threads. This twill weaving produces a diagonal ribbing that distinguishes it from cotton duck. While a denim predecessor known as dungaree has been produced in India for hundreds of years, denim itself was first produced in the French city of Nîmes under the name sergé de Nîmes.
Etymology and initial popularity
The word 'denim' derives from French serge de Nîmes 'serge from Nîmes'.
Denim has been used in the United States since the mid-19th century.Denim initially gained popularity in 1873 when Jacob W. Davis, a tailor from Nevada, manufactured the first pair of rivet-reinforced denim pants. The popularity of denim jeans outstripped the capacity of Davis's small shop, so he moved his production to the facilities of dry goods wholesaler Levi Strauss & Co., which had been supplying Davis with bolts of denim fabric.
Throughout the 20th century denim was used for cheap durable uniforms like those issued to staff of the French national railways.
In the postwar years, Royal Air Force overalls for dirty work were named "denims". These were a one-piece garment, with long legs and sleeves, buttoned from throat to crotch, in an olive drab denim fabric.
Creating denim
All denim is created through generally the same process:
Cotton fiber is spun into yarn
Some of the yarn is dyed, some left white
The yarns are woven on a shuttle loom or projectile loom
The woven product is sanforized
Yarn production
Most denim yarn is composed entirely of cotton. Some denim yarn may use an elastic component such as spandex for up to 3% of the content to allow the final woven product to stretch. Even such a small amount of spandex enables a stretching capacity of about 15%.
Dyeing
Denim was originally dyed with indigo dye extracted from plants, often from the genus Indigofera. In South Asia, indigo dye was extracted from the dried and fermented leaves of Indigofera tinctoria; this is the plant that is now known as "true indigo" or "natural indigo". In Europe, use of Isatis tinctoria, or woad, can be traced back to the 8th century BC, although it was eventually replaced by Indigofera tinctoria as the superior dye product. However, most denim today is dyed with synthetic indigo dye. In all cases, the yarn undergoes a repeated sequence of dipping and oxidation — the more dips, the stronger the color of the indigo.
Prior to 1915, cotton yarns were dyed using a skein dyeing process, in which individual skeins of yarn were dipped into dye baths. Rope dyeing machines were developed in 1915, and slasher or sheet dyeing machines were developed in the 1970s; both of these methods involve a series of rollers that feed continuous yarns in and out of dye vats. In rope dyeing, continuous yarns are gathered together into long ropes or groups of yarns – after these bundles are dyed, they must be re-beamed for weaving. In sheet dyeing, parallel yarns are laid out as a sheet, in the same order in which they will be woven; because of this, uneven circulation of dye in the dye bath can lead to side-to-side color variations in the woven cloth. Rope dyeing eliminates this possibility, because color variations can be evenly distributed across the warp during beaming.
Denim fabric dyeing is divided into two categories: indigo dyeing and sulfur dyeing. Indigo dyeing produces the traditional blue color or shades similar to it. Sulfur dyeing produces specialty black colors and other colors, such as red, pink, purple, grey, rust, mustard, and green.
Weaving
The thickness of denim can vary greatly, with a yard of fabric weighing anywhere from 9 to 32 oz,with 11 to 14 oz being typical.
Although quality denim can be made on either loom, selvedge denim has come to be associated with premium products since final production that showcases the selvedge requires greater care of assemblage.Most denim made today is made on a shuttleless loom that produces bolts of fabric 60 inches or wider, but some denim is still woven on the traditional shuttle loom, which typically produces a bolt 30 inches wide. Shuttle-loom-woven denim is typically recognizable by its selvedge (or selvage), the edge of a fabric created as a continuous cross-yarn (the weft) reverses direction at the edge side of the shuttle loom. The selvedge is traditionally accentuated with warp threads of one or more contrasting colors, which can serve as an identifying mark.
Post-production treatment
Particularly with denim jeans, a significant amount of the aesthetic treatment of denim occurs after the denim has been cut and sewn into the final garment.
Many denim articles are washed to make them softer and to reduce or minimize shrinkage even beyond what sanforization prevents. Significantly washed denim can resemble dry denim which has faded naturally over extended use. Such distressing may be supplemented by chemical treatments or physical techniques such as stone washing.
Changes in appearance due to use
To facilitate the natural distressing process, some wearers of dry denim will abstain from washing their jeans for more than six months.
Most dry denim is made with 100% cotton and comes from several different countries.Over time dry denim will fade, considered fashionable in some circumstances. During the process of wear, fading will usually occur on those parts of the article that receive the most stress. On a pair of jeans, this includes the upper thighs, the ankles, and the areas behind the knees.
Patterns of fading in jeans caused by prolonged periods of wearing them without washing are a way of "personalizing" the garment.Such patterns include:
honeycombs – meshes of faded line-segments that form behind the knees
whiskers – faded streaks that form radially from the crotch area
stacks – irregular bands of fading above the ankle caused by according of the fabric due to contact with the foot or shoe
train tracks – fading along the out-seams due to abrasion
