Eman is a writer and textile engineer. She obtained her bachelor's degree in textile science from the Faculty of Applied Arts.
Denim is made from 100% cotton and one of the oldest fabrics in the world. It is the garment commonly preferred by all age groups and, due to its circulation, a lot of development work has been done in the last few decades.
Denim fabrics are available in many colors, but the most popular is indigo denim, where the twist thread is dyed while the weft thread is left white. As a result of the twisted-faced twill weaving, blue warp threads dominate on one side of the fabric, while white weft threads dominate on the other side. Jeans made of this fabric are mostly white inside.
Annually, about 15 billion meters of denim fabrics are produced globally to manufacture about 10 billion items of clothing. Denim fabric is used to make aprons, capri pants, cloth face masks, dresses, hats, jackets, jeans, overalls, shorts, skirts, suits, shoes, sneakers, belts, handbags, wallets, upholstery, lampshades, and various other common consumer items.
The global denim market was valued at $56,178.1 million in 2017 and is expected to experience an annual growth rate of 5.8% during 2018–2023.
The industrialized countries that produce the most denim are China, Turkey, Bangladesh, India, Pakistan, Mexico, and Brazil.
In this article, we will take a look at nearly every aspect of this beloved fabric, including its history, properties, types, manufacturing processes, dyes, uses, and care instructions.
A Brief History of Denim
The story begins with the Dungaree, which is another word for denim. This sturdy fabric was first designed for trousers in India and was worn by Portuguese sailors.
Dungaree fabric began as a common Indian cloth, and then became a sailor's costume. In the United States and Australia, dungaree was popular as durable work pants worn by shepherds, farmers, cowboys, and miners.
The name denim referred to a fabric called Serge de Nimes after the textile city in southern France. The name may have been shortened to "denim" or "nim" when the fabric was imitated in English factories.
Jeans date back to the Italian port of Genoa, a nod to the sailors' trousers as well. There may be contact with the Indian Dungaree as well, through the Red Sea trade or the Mediterranean links with Portugal.
The uniform for American sailors since 1916 has been jeans with a white cotton hat. Sailor trousers, including those worn by the US Navy in the 19th and 20th centuries, were called dungarees. Trousers were rough and durable fabric used to make sails and tents as well. Sailors needed wide-legged trousers for ease of wearing and operating on the ship in wet conditions.
Types of Denim
- Raw Denim or Dry Denim: This refers to jeans that have not been wet and treated in any way before they were purchased. These jeans can be left undashed for six months to a year until they take on the body shape. It is important to pre-wash raw denim before wearing it.
- Stretch Denim: It is incorporated with stretchy synthetic fiber like lycra/spandex, which gives it stretch.
- Sanforized Denim: This fabric has been treated to not shrink after washing.
- Colored Denim: The blue color or shades close to blue are attained through indigo dyeing. Sulfur dye creates other colors of denim fabrics, such as black, pink, gray, green, red, etc.
- Black-Black Denim: This is an expression used for denim, where the warp thread is black instead of blue and is also dyed black after weaving.
- Waxed Reverse Denim: This is a fabric that has a layer of wax on the backside to be waterproof. It is mostly used to make bags.
- Left-Hand Twill: This is a weave in which the grain lines extend from the top left-hand corner of the fabric towards the bottom right. It usually occurs in piece-dyed denim where left-hand twill fabrics are woven from single plied yarns in the warp. Left-hand twills have a softer hand feel after washing than right-hand twills.
- Selvage Denim or Self-Edge Denim: This refers to denim fabric with edges finished with a ribbon that is usually orange or red in color. This denim is distinguished by quality. Japan is the largest producer of this kind of denim fabric.
- Poly Denim: This is a fabric blended with polyester fibers. It has a very soft feel, is easy to care for, and has a somewhat stretchy feel. Sewing of jackets, shirts, and hats is very popular.
- Crushed Denim: This fabric is weaved and treated to look permanently wrinkled or crushed.
- Open-End Denim: This was introduced in the 1970s. Cotton fibers are "mock twisted" by blowing them together. Open-end denim is bulkier, coarser, and darker, as it absorbs more dye.
- Rapid Skying: This is a patented oxidation process developed by Tessitura di Robecchetto Candiani in 1992 that speeds up the skying phase of indigo dyeing.
- Thermal Denim or Double Denim: This fabric features a lightweight, glued denim fabric. It makes the garment look like it's quilted.
- Ring/Ring Denim: This fabric uses ring-spun yarn for both warp and weft. It is possible to combine the warp ring-spun weave with an open-end weft to obtain a lot of durability and feel for the traditional ring/ring denim at a low cost.
- Acid Wash Denim or Marble Denim: This refers to the finishing achieved in the denim fabric using a chlorine-soaked pumice stone. The color of the fabric fades from corrosion and creates an attractive contrast to the indigo color. Then the fabric is rinsed, smoothed, and dried.
- Bull Denim: This is an extremely sturdy and tough fabric due to its 3x1 twill construction. This denim is very durable and heavy, mostly used for upholstery and home decor.
- Ecru Denim: This fabric has the natural color of denim without dyeing.
- The Printed Denim: This is colored with different graphics, often in contrasting colors and intended to respond to fashion trends.
- Reserve Denim: A new use of denim turned inside-out to give jeans a different look.
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Types of Jeans Based on Cuts
- Skinny Jeans: These are cut to be tight all over the leg, from the thigh to the ankle. They are usually made of stretch denim to be easy when wearing or taking off.
- Boot-Cut Jeans: These types of jeans work well with ankle boots.
- Straight-Leg Jeans: They appear to have a straight up-and-down fit through the entire leg, and they can be on the baggy side, relaxed-fit, or the fitted kind.
- Wide-Leg Jeans: This style of jeans is cut wide all over the leg, start to flare around the mid-thigh, and then continue down into the wide-leg opening.
- Bell-Bottom Jeans: This type of jeans has a snug fit through the thigh and expands from the knee to the leg opening.
Properties of Denim
- Denim is very soft, breathable, and comfortable to wear.
- The fabric is very durable and does not snag or tear easily.
- It absorbs water and dye easily.
- The fabric dries slowly.
- Denim resists static electricity build-up.
- It wrinkles easily.
- It holds up well to heat and detergents.
Let's take a look at some of the different dyes for denim.
When denim is mentioned, indigo dye comes to mind. Since the advent of denim, indigo dye has been associated with it. Indigo was a valuable plant found in Egypt, Babylon, Greece, Rome, China, and India. By the 11th century, indigo plants were cultivated in Islamic Spain. Currently, however, the plant dye has been replaced by chemical indigo dyes that are easier to manufacture.
Nevertheless, indigo is unique in its ability to impart surface color due to partial penetration into the cotton fibers. When the indigo-dyed cotton yarn loosens, the inner layers remain uncolored.
The chemical formula of indigo is C16H10N2O2. Indigo dye is a dark blue crystalline powder that sublimates at 390–392°C (734–738 °F). Indigo dyes are not soluble in water ether or alcohol, but are instead soluble in nitrobenzene, chloroform, and concentrated sulfuric acid.
The unique feature of indigo-dyed denim is that it can achieve washing effects on repeated washings without losing color freshness. Another important feature of indigo is that, unlike many other dyes, denim dyed indigo does not pose health risks.
Technical features of indigo include the ability to dye at room temperature, preferred shades from black to dark blue that are not very glossy, and the low indigo solution is not sensitive to water hardness—this allows for a gray dye or minimal pre-treatment of the cotton, and repeated washing removes the dye slowly without losing its freshness.
Direct dyes are used to dye jeans into light colors for the higher fashion market. Also, direct dyes can be used to color denim fabrics by adding them to the final formula.
There have been attempts to apply reactive dyes to indigo machines, but dye control is nearly impossible due to the large dye boxes in most indigo equipment, as much of the dye is decomposed before it interacts with the cotton. Therefore, reactive dyes should be placed in a small box, then dried, chemically primed, and evaporated. The only practical alternative for most denim companies is to apply reactive dyes during sizing with special procedures.
There are few vat dyes that can be mixed with indigo for casting; however, pure tub colors are best applied to denim with specially designed rope ranges with an extra set of drying cylinders, steam bowls, and small boxes for dye pad, dry chemical pad, and steam methods. However, vat dyes produce shades with high fastness properties. Thus, the classic denim fabric look is hard to come by.
Sulfur dyes are low cost and can be applied to indigo machines, pad dyeing machines, and garment dyeing machines with properly designed methods. Sulfur dyes have a more natural look than reactive or directed dyes, have a softer appearance, and allow for versatile washing effects in wash operations. Therefore, among the different dye classes other than indigo, sulfur dyes are the most popular and are used for the wrapping, decorating, or dyeing of indigo-dyed garments to produce a variety of shades with a great look.
Because of the high pollution of dye bath residues, sulfur dyes are slowly being phased out in the West but are still widely used in China. Recent advances in dyeing techniques have allowed the replacement of toxic sulfide-reducing agents. Glucose is now used in the primary solution, and both low-sulfide and non-sulfide products are available.
Denim Manufacturing Process
The cotton is taken out from the prepacked bales to check before undergoing the carding process.
In carding, the cotton is run through machines containing brushes with bent wire teeth. The function of this process is to clean, detangle, straighten, and hold the cotton fibers together. The resulting fiber is called silver.
Other machines then join several silvers together to be pulled and coiled to make the threads stronger. After that, these threads are placed on spinning machines that wind and stretch the fibers to form the yarn.
Denim is dyed before being woven. The dye used is usually synthetic indigo.
The denim is dipped into the dye bath several times so that the dye forms several layers. This is the reason that blue jeans tend to fade after washing.
A small amount of sulfur is applied to fix the indigo dye. The threads are then treated with a group of starches to make the thread stronger and stiffer.
The threads are woven on large looms without a bobbin. The blue threads are woven with white threads. But since the blue threads are stuck together more closely than the white threads, the blue color dominates the fabric.
5. Cutting and Sewing
Denim fabrics are cut according to the design, then they go to sewing machines to be stitched by industrial sewing machines. On the sewing floor, skilled workers sew according to the pre-defined seams and seam allowances. The industrial machine can sew very quickly, so workers must be highly skilled to avoid injury.
There are many types of denim finishing:
- Scraping is the process of making clothes look worn and old by rubbing the surface of the fabric, causing abrasion.
- Aged is a type of wet treatment that gives denim fabric an industrial look through prolonged wear.
- Bleach is a chemical process used to make denim fade. Liquid bleach is an aqueous solution of sodium hypochlorite, and the dry powder is calcium hypochlorite.
- Desizing is a washing process that is used to soften denim. During this process, the amylase enzyme removes starch from the fabric to give softness to denim.
- Atari is a Japanese term that describes the selective fading of wrinkle edges. The most common areas for Atari are the seams, on the front and back of the knees along the hem, the top of the thigh, and on belt loops.
- Grinding creates the appearance of age. It is applied to hems, seams, belt loops, pockets, and waist belts.
- Pumice stones are volcanic stones used for stone washing garments. They are popular because of their strength and light weight. They are used to soften denim during the laundry process. The stone washing process has many problems, such as damage to washing machines and clothes, increased labor to remove dust from finished garments, water pollution, and back staining.
- The acid color of indigo jeans gives sharp contrasts. This process is done by soaking the pumice stones in chlorine and letting the pumice stones create contrast. Acid-dyed, indigo-dyed denim tends to turn yellow after a wet treatment. The main cause is residual manganese due to incomplete neutralization, washing, or rinsing.
- Overdyeing is a process that can take many forms, as the blue thread can be black in color, otherwise known as blue change black. Blue or black denim can also be dyed in contrasting colors for unusual shadow effects. Also, indigo jeans can be bleached to a neutral color and then brightly dyed.
- Enzyme washing is a process used to reduce the negative effect of stone washing, in which denim fabric is washed with enzymes. The enzyme breaks down the surface cellulose fibers of the denim fabric and removes them during washing. Some of the indigo dye is also removed from the surface of the fabric.
- Petroleum washing is a method of finishing denim developed in 1992 by American brand Willi Wear. In the process, the left-hand denim is enzyme washed until it loses most of its color. It is then dyed and put into a silicone lotion, which gives the fabric an oily coating.
- A resin bake crease is a process used to replicate the look of permanent creases, which normally would occur after repeated wear on specific areas.
How to Care for Denim Fabrics
- Clean the denim with cold water. Using warm water will remove the color from the fabric and will also cause it to shrink.
- If possible, use cold water cleaner designed for darker colors.
- Turn the jeans inside out before putting them into the washing machine.
- To remove stains, hand wash the denim in the sink or other large container for best results.
- If you are not obliged to dry heat, it is best to hang denim fabrics and let them air dry, as this will keep them for longer.
- Story of Denim Blue Jeans Across the Eras - Indian Ocean History
- Indigo ring dyeing of cotton warp yarns for denim fabric - Mohammad Gias Uddin
- Analysis of Physical & Chemical Properties of Cotton: Jute Blended Denim After a Sustainable (Industrial Stone Enzyme) Wash - Sazid Elahi et al.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
© 2021 Eman Abdallah Kamel
Eman Abdallah Kamel (author) from Egypt on February 04, 2021:
Thank you, dredcuan, for reading the article. I agree with you that there are many types of denim and designers are still inventing new ones. I appreciate your visit and comment.
Travel Chef from Manila on February 04, 2021:
Interesting article. I love how detailed you've presented all of this information. I never knew there are so many types of denim.
Eman Abdallah Kamel (author) from Egypt on February 03, 2021:
Thank you, Linda, for reading the article. I also love the historical aspect, whether in reading or when writing. I always appreciate your comments.
Eman Abdallah Kamel (author) from Egypt on February 03, 2021:
Thank you, Liz. You are right denim fabrics are very popular and durable. I always appreciate your visit.
Linda Crampton from British Columbia, Canada on February 03, 2021:
This article is full of interesting information and detailed facts. Thank you for sharing your knowledge, Eman. I was especially interested in reading about dungarees. I remember using this term for jeans in my childhood.
Liz Westwood from UK on February 03, 2021:
This is a fascinating article about a hugely popular and durable fabric. I appreciate the detail and volume of interesting information that you have included.