Ever wondered how is silk made? Silk is considered one of the most luxurious and expensive fabrics since the silk production process is tedious and time-consuming. There have been controversies as to the traditional and primary method of silk creation, leading to the development of more ethical, modern silk-making techniques.
How Is Silk Made - The Traditional Technique
The traditional way of producing silk hasn’t changed a lot, even with technological advancement. That is the main reason why it’s still laborious and requires a lot of time. This technique involves the assistance of the larvae form of certain silkworm species.
How is Silk Made Using Bombyx Mori
The most common silkworm used in silk manufacturing is the Bombyx mori which produces some of the finest silk fabrics. The successful production of the sturdy, elegant silk fabric using Bombyx mori involves nine or 10 steps.
How is silk made steps:
- Sericulture or Harvesting
- Stifling and Sorting
- Reeling and Twisting
- Dye Application or Treatment
- Printing (Optional)
Sericulture or Harvesting
Simply known as mulberry cultivation, this is the process of gathering silkworms and harvesting their cocoons to collect the materials needed for silk production. Producers carefully select succulent and tender mulberry leaves and then place them in a tray.
Each leaf will have one silkworm that will be allowed to feed on a mulberry leaf to help the insect grow. At times, two silkworms are placed in one nest or leaf to create one cocoon that will form two different fibers, thin and thick. The final fabric made out of this is Dupioni silk.
After about six weeks, the silkworms grow up to three inches (7.5cm) and stop feeding. This stage is also when they start to raise their heads and are ready to spin their cocoons.
The silkworms then start to rotate about 300,000 times in a figure of eight fashion. The complete process will take approximately around three to eight days. It’s expected that one silkworm will produce 100 meters of a silk strand held together by sericin or natural gum.
Stifling and Sorting
After the completion of the spinning process, the silkworms will enclose themselves in the silk strand they produced. For the pupas not to hatch and break the silk cocoons, they need to undergo stifling or the process of exposing the cocoons to steam or gas. This method will also help dry out the cocoons to preserve them longer.
After that, the cocoons need to get sorted out based on quality and other features, including color, shape, length, and luster. Those with defects, such as mold growth, urine stains, and perforations, would be thrown out.
The cocoons are then placed in boiling water to help soften them and easily find the fiber strand’s end needed for unwinding. This process will also dissolve the gum or sericin without damaging the fibers and ensuring the collected threads are intact. The removal of gum is critical since it can make the silk rough and difficult to dye.
After the boiling process, the cocoons might still have loose fibers or a fuzzy layer that contains uneven and broken filaments. To remove these filaments, the cocoons need to undergo deflossing for a cleaner look, easier next processes, and better market value. This step involves brushing or peeling off the layer by hand.
Reeling and Twisting
The next step is to unroll the cocoon and combine the silk filament to turn the cocoons into threads and create a single silk strand. Usually done manually, manufacturers now use automated machines that will unravel and dry the silk simultaneously.
Since one silk strand is too thin, some manufacturers reel multiple filaments together, usually from two to 20 cocoons, depending on how thick the final silk yarn will be.
The next step is to remove the yarn from the reel and then twisted it into spiral circles, forming skeins or bundles of yarn. The number of twisting and silk threads used will depend on the types of silk the manufacturer intends to produce.
Dye Application or Treatment
The next step in the process of silk production will depend on the type of silk being produced.
How is Silk Made when Dye-Based
To give the silk threads some color, they get exposed to dyes. The kind of dye used depends on the manufacturer.
The oldest and still most popular silk thread dyeing method is with the use of natural dyes, usually indigo fruits or leaves. The leaves or fruits are placed in water to make a dye solution. The bundled threads are then soaked in the solution. This process gets repeated for several days to ensure the threads have the proper color quality and tone.
Technological advancement enabled manufacturers to dye silk threads for a broader range of shades and colors. It involves reactive or acid dyes that are convenient to use, have high applicability, wet-fast, and are brilliant.
The problem with these types of dyes is that they require many auxiliary agents, produce high amounts of wastewater, and have low dyeability.
The process is almost similar to the traditional method, wherein the manufacturers immerse the silk threads in a dye bath. The thread, though, can either be fed through two cylinders or fixed to a round-shaped jig.
How is Silk Made when Weighted
For weighted silk production, the threads need to undergo treatment using synthetic resins and heavy metal salts. Some manufacturers also add dyes to color the threads. The treatment process will help the silk become heavier, which is a more expensive type of silk.
The use of a spinning wheel to spin silk threads has long been part of the silk production method. Today, manufacturers utilize a modern tool with the same principle that can do the job more quickly. This can be either ring-spinning, mule-spinning, or hand-spinning. The spinning step helps unwind the dyed silk fibers so that they lay flat in preparation for weaving.
The weaving process comes in different types, and the most common ones are plain, twill, and satin. Regardless, this step involves the process of interlacing two thread sets to create a lock and develop a sturdy, uniform fabric.
Some silk pieces need a particular design or pattern. Manufacturers do this through screen printing or digital printing with a specialty textile printer's help. Manufacturers use either hand-drawn or digitally-made artworks on silk fabric.
The actual end of how is silk made is weaving. However, the finishing step is important since it gives the fabric its sheen. Some chemical treatments can also help make the fabric crease-proof and resistant to fire.
How is Silk Made Using Other Silkworms
Some manufacturers use either Antheraea pernyi, Antheraea mylitta, or Bombyx croesi that are usually grown in China, India, and Japan. The process is the same but uses oak leaves. Likewise, the produced silk is color brown, plus, heavier and coarser than the mulberry silk. The end product is known as the wild silk in Japan and Tussah silk in India and China.
How Is Silk Made - The Cruelty-Free Method
The conventional method of how silk is made sparked and still sparks a lot of controversies regarding animal cruelty. Mainly because of exposing the silkworms to gas or heat and boiling them while they’re still alive. Hence, the creation of peace, eri, or ahimsa silk.
The process usually involves the silkworm Philosamia rinini. Compared to the traditional procedure, the silk cocoons get harvested and processed after the moth hatches from its cocoon. The moth will secrete a liquid that will help create a hole where it will hatch and then break the long, continuous silk fiber to create short ones. The next processes begin from spinning to finishing.
Although it’s a cruelty-free method, the silk produced is more expensive. That’s because of the extra ten days needed for the larvae to grow and hatch. Likewise, the cocoons only produce about one-sixth of the usual fiber volume.
That said, this process of making silk isn’t free of controversies since the silkworms still experience some form of suffering. Some claim that these silkworms don't get provided sufficient food and are forced out of their cocoons prematurely.
Others also claim that the female moths might be crushed to death. On the other hand, the males often get refrigerated and released when needed for breeding and then discarded when they can no longer mate.
How Is Silk Made - With the Help of Spiders
Not as popular and common as silkworm silk, spider silk has thin, narrow fibers that are strong and lightweight and have excellent elasticity. It can also focus light effectively and shrink when exposed to humidity.
Most spiders have silk-producing glands in their abdomens. The silk produced is initially liquid and needs to be pulled out of their bodies to create a solid silk strand. Manufacturers usually sedate the spiders with carbon dioxide. They then pull the silk from the spider’s body using a spinneret’s tweezer and then attach it to the spool using glue before the motor gets started.
How Is Silk Made - In Conclusion
The natural silk fabric has a good quality and sheen that one can use in producing multiple items, such as clothes, curtains, and pillowcases, that require special washing and ironing. The different types of silk usually depend on what insect the manufacturer uses, and some added steps in the process.
In terms of how is silk made, the most commonly used are silkworms and spiders, leading to some ethical and animal cruelty issues that some manufacturers have addressed. That said, if the process concerns you, ensure you purchase silk with certified eco-friendly or cruelty-free certification or seal.