Silk is a fabric that has a long and rich history. Silk fabric, which had its roots in 27th century B.C. China, has been mentioned throughout history from ancient tales of emperors and empresses to the time of King Solomon in the Old Testament. Silk is a fabric that paints a colourful history, both interesting and romantic – and it’s no surprise, with its soft, lustrous quality, it was a fabric akin to royalty and the gods.
The art of making silk fabric was kept secret by the ancient Chinese for thousands of years. Seeing as silk was a valuable commodity, the Chinese became the exclusive producer and source of silk for the rest of the world. As a result, silk had opened up trade routes between Asia, Europe and Africa – routes which are now popularly known as The Silk Road. Although the knowledge of silk creation eventually did reach other countries, China is still in the forefront of silk fabric production up to today.
In nature, silk is a natural fibre produced by certain insects and spiders when making cocoons and webs. The silk fabric that we commonly know of is the one produced from the cocoon of silkworms.
Silkworms in fact are not worms, but caterpillars of the moth scientifically known as Bombyx, mori. Like many caterpillars, the silkworm spins itself a cocoon of silk in which it pupates. This cocoon is especially thick and is usually composed of a long, single thread. To produce the silk fabric, the cocoon is unravelled. The thread - called the filament - is then used to weave the silk fabric.
The Bomyx mori caterpillar is native to China, but has also been introduced to many countries. The caterpillar, which takes about a month to develop, feeds on the leaves of the mulberry tree.
Silk farming or sericulture, is believed to have first started in China at around 2640 B.C. A very involved process, silk farming not only focuses on rearing silkworms that produce the silk, but it also entails the care of mulberry trees that provide the leaves which the worms eat.
Silk farming starts with the proper selection and care of the moth eggs. These silkworm eggs are then kept in cold storage until mulberry trees start budding, then are introduced to a warmer temperature to hatch. Once hatched, these voracious silkworms are fed with mulberry leaves. It has been estimated that at least 485 pounds of chopped mulberry leaves are required to produce 2 pounds of raw silk.
As soon as the silkworms have fully developed and are ready to spin their cocoons, they are taken to the spinning racks. Spinning racks are wooden racks sectioned off with cardboards where silkworms anchor their silk filaments and build their cocoon.
Although some of these cocoons are kept for breeding purposes, most are unwound to make silk. As an emerging moth will break the cocoon, the chrysalis inside is killed by hot air or steam. This also dries the cocoon and preps it for storage. Silk cocoons are then sorted and graded according to quality.
Once the silk cocoons have been sorted, they are now prepared for reeling. Reeling is the term used to describe the process of unravelling the silk filaments from the cocoon. The cocoons are first put into hot water in order to soften them. The softened cocoons are then slightly brushed to find the ends of the filaments so they can be unwound.
In ancient times, reeling was a long and arduous task that involved many hours of labour. Now, the process is fully automated, with machines reeling up to 11 pounds of raw silk every eight hours.
Silk Yarns and Fabrics
The reeled silk is oftentimes subjected to a process called throwing. Throwing is where the silk strands are twisted together with other silk strands, to form a thicker, stronger, multithreaded silk yarn. Examples of silk yarns that are obtained by throwing are: crepe yarns which produce silk crepe fabric, characterized by a crinkled or puckered surface; organzine, a very strong kind of silk yarn used for weaving and knitting; and doupion, or dupion yarns which are produced by reeling from one single cocoon spun by two silkworms that have nested together – weaving this yarn results in a rough silk fabric with a coarser texture.
There are many types of silk yarns that, when woven, produce the different types of silk fabrics that we now know today. Some examples of fabrics that come from woven silk are chiffon, satin, twill, tafetta, brocades, damask and velvet.
With today’s technology, cheaper and more durable synthetic fibres have been introduced to replace silk. Despite this, the allure of genuine silk has not waned. Silk, with its rich history, and the careful artistry involved in producing it, still remains, as it was, many years back, a coveted luxury fabric loved by many.
Copyright d'Italia 2012