Cotton----- the origin of Denim
All kinds of denim are made out of cotton. As the important base of denim, cotton directly influences the washing and duration of the denim. Hence jeans makers are more and more focusing on selecting the best cotton.
“Zimbabwean cotton” has been frequently used as the selling point in the jeans market. However, not only Zimbabwe, but also Burkina Faso, Benin, Uzbekistan, United States, Egypt, Australia and Chinese Xinjiang ect. are important cotton production bases. Cotton from different production places and grades has different quality leaves. Although there are so many cotton production places, finding the suitable cotton is not an easy job. Only the one with high intensity, low impurity and moderate micronaire value can stand the later dyeing and washing process.
Spinning----the cut-off point of hand feeling
After washing a cluster of cotton, the cotton has to be twisted before weaving. The hand feeling of the denim, hard or soft, depends on the intensity of twisting yarns, and the sort order, density, strength of weaving. The industrialized twisting yarns are different from the traditional twisted ones.
The industrialized way first puts the raw cotton into the twisting machine, condenses the cotton fiber and comes out with yarns. Then the yarns are made into tower shape bobbin by hands. Lastly the yarns will go through a carding machine, attenuated to form a shaft diameter, and waiting for dyeing. The twisted yards are fluffy and wear-resistant, even, brightly dyed, with low intensity.
Many jeans brands in Japan still stick to the traditional way of twisting yarns, for more compacted and intense yarns. However, the traditional way is not efficient enough to fit the bulk production.
Dyed yard----- the combination of traditional and industrialized production
Dyeing process should go from light to deep, including coloring, oxidation, purified and color fixing. The second dyeing should not wait till the yarns are dry from the first one. Every time the yarns are put into the dye vat, it should be considered as being dyed once. Going through the dyeing process again and again makes the deep colors of Indigo. The traditional way of natural dyeing is much more complicated than the industrialized way. It usually needs to go through the dyeing process for 20 times, and the cotton core of the warp yarns is almost dyed to the central part. In this way there will be more gradations of colors, hence many ancient jeans still use the traditional dyeing way to keep the colors similar with the original ones.
Regarding the dye, there are two kinds of dye for denim, namely the natural dye and the artificial synthesized dye. The natural dye is the blue one extracted from the Indigofera plants. The natural dye is safe and anti-bacteria. The artificial indigo blue can never achieve the same effect. The discovery of artificial synthesized dye overcomes the limitation of natural indigo blue. However, the yarns dyed with artificial synthesized dye are tend to be dark and with strong color fix. It is hard to make light colors, not as safe as the natural one. Environmental friendly will stay as the theme in the following years. Denim dyed with natural dye is definitely more competitive in the market, pushing the discovery of environmental artificial synthesized dye.
The secret of blue top and white back denim effect: when weaving, make indigo blue warp yarns and original weft yarns as three on top and one at the bottom position. At the same time, the twill should be rightward. That is how the indigo blue face and original color back denim come into being.
Weaving-----first secret of increasing jeans value
Besides raw cotton, fabric is another important factor for jeans. The duration of fabric directly influence the later made jeans. Different fabric thickness, composition, weaving methods lead to different denim. Many ancient jeans add their own value by using unique fabric and weaving methods.
The denim thickness varies from 4.5d to 17 oz. The more ounce it weights, the thicker it will be, thus with longer duration. 4.5d fabric is very thin, usually applied to female jeans for summer ect. While the 14d to 17d ones are thick enough to make heavy ancient jeans.
Regarding the denim types, there are plain, twill, zig-zag, interlacing dot, slubby, dark fringe and jeans flocking ect.
Base on composition, the denim can be sorted out as the 100% cotton, elastic (with lycra), linen/ cotton blended, tencel ones. Most jeans in the market now are made with blended fabric. Female jeans usually use elastic fabric for better fit.
Many ancient jeans brands prefer using the traditional weaving machines to weave 29 inches width denim fabric for different effect and hand feeling.
After weaving the fabric, there is one more important process, that is sizing, making the fabric harder. This action makes the later cutting process easier since harder fabric is more convenient for cutting.
Washing-------the magic hand of creating value
Washing turns a normal jean into various styles by using chemical lotion, machines or handwork. The jeans can come out with different patterns or even ancient effect.
There are so many different washing methods, such as Garment Wash, Stone Wash, Enzyme Wash, Sand Wash, Chemical Wash, Bleach Wash, Destroy Wash. Stone wash is the most commonly used and basic process for making jeans. Stone wash creates one kind of effect which first appeared and is most needed. During the washing process, pumice stones in certain sizes are put into the water, creating the friction between the jeans and the stones. After washing, wearing appears on the waist band, pockets and the seams. The fabric seems to be gray and old.
Compared with machine washing, handwork on the jeans attracts more attention. Hand brush means that people use abrasive paper or cotton cloth with mineral chameleon to make different patterns on the jeans. Chemical reaction occurs when jeans meet with mineral chameleon, then fading happens.
To some extent, the color of the final jeans depends on the later process, namely machine washing and handwork. Moreover, the colors of denim, which comes out from different dye vats, are hardly the same. That makes the uniqueness of denim. The final hand work is also considered to be an effective way to create exceptional denim.