Some textile processes
To convert wool fibre into throws, blankets, fabric and accessories, a sequence of processes has to be followed. Expert knowledge and judgement are required at every step.
1. Fibre Selection
There are many different styles and qualities of wool grown world wide, each with their own characteristics. It is essential at this stage that the most appropriate fibre is selected for the end product.
Points for consideration would include
- Micron – measure of fibre diameter
- Staple length – fibre length
- Style – crimp, regularity and colour
- Cleanliness – contaminants such as vegetable matter
Colour can be imparted to raw wool fibre, spun yarn or woven fabric depending on the end product. Dyeing requires dye stuffs, water, heat and agitation.
Blends can be made of different colours of the same fibre or different types of fibre, e.g. wool and silk, wool and cashmere. At this stage the fibres are sprayed with a coating of light oil which protects them in the subsequent processes and makes them easier to manage.
Blending various colours of fibre together prior to carding and spinning creates traditional Scottish woollen yarns, called ‘mixtures’. These are a typical characteristic of Scottish Tweeds.
After teasing, the wool is fed into a hopper and from there it goes into a carding machine which mixes and straightens all the fibres in preparation for spinning. Carding converts a continuous web of fibres into individual ribbons of specified weight per unit length, which can then be spun into yarn. These ribbons are known as rovings. Rovings are then converted into yarn by spinning.
Spinning involves drawing out and inserting twist to the roving. Twisting imparts strength to the yarn allowing subsequent processes to take place. The thickness of the yarn is determined by drawing the rovings out by a pre-determined degree. Different regional systems of the measurement of yarns were developed in the early years of the British textile industry and many are still in use today.
- Gala Cut – number of hanks each measuring 200yd in 1lb
- Yorkshire Skeins – number of hanks each measuring 256yds in 1lb
Depending on the end use, the resulting yarn may be plyed together several times. The yarn is automatically checked for evenness at frequent intervals throughout the carding and spinning process, to ensure that the final woven product will be as flawless as possible.
There are an infinite variety of ways in which the warp ends and the weft picks can interlace. The simplest of all is Plain Weave, where alternate warp ends pass over and under weft picks. Varying the sequence in which warp threads are raised and lowered can create complex patterns.
Yarn selection, the sequence of warp and weft colour patterns, the density of threads and the finish of the fabric also play a crucial role in fabric design.
Preparation for weaving
Warping is the preparation of the ‘warp’ threads, which run vertically from top to bottom of the cloth. They are set out in a pre-determined colour pattern, which is created by the designer. The number of threads in the warp varies according to the fineness of the yarn and the density and width of the fabric required.
Warping was originally carried out by hand on warping stakes, a process which is still sometimes used for short sample lengths and design blankets. For production runs the warp yarns are wound from cones onto warp mills in the pre-determined colour sequence.
When the warp is ready it is wound onto a circular beam and ‘drawn’ through individual heddles onto shafts. These shafts are raised and lowered in the loom to determine the warp and weft interlacing
From the heddles the threads are ‘sleyed’ through a reed, which is essentially a comb, to determine the fixed width in loom and the regular spacing of warp threads.
Weaving is the introduction of the weft yarn, known as picks, which run horizontally across the fabric. Like the warp the weft threads are inserted in a pre-determined density and colour sequence.
11. Greasy darning
When fabric comes off the loom, it is known as a web. It is inspected thoroughly and any faults are mended or darned before going on to wet finishing.
Scouring is the process of washing the fabric to remove oil, grease and dirt.
Milling shrinks and thickens the fabric. Now carried out by machine, this was originally achieved by stamping on the fabric in water, from which comes the old Scottish term ‘waulking’.
After wet finishing the fabric is held out to a given width and then dried by passing it over heated rollers in a Stenter. Before such machines were available, fabric was hung up on hooks in the open air, giving rise to the expression ‘to be on tenterhooks’.
Some fabrics, particularly scarves and rugs, go through a raising process. The fabric is passed over rollers covered with sharp wire to gently pluck fibre to the surface of the fabric and impart a soft handle.
Some fabrics require to have a bare surface, depending on end use, and these are ‘shaved’ in a cropping machine.
17. Clean Darning
Prior to final finishing, such as pressing, the fabric is once again carefully inspected any minor faults are repaired.
18. Final Finish
Any final finish dependant on the fabric’s end use now takes place and the fabric receives a final inspection and is rolled prior to despatch.
Some Textile Related Sayings
On tenterhooks – the tension of waiting for news, as with a cloth stretched on tenterhooks to dry.
Cut from the same cloth – sharing characteristics, like two items made from a single piece of fabric.
Dyed in the wool – unchanging, as wool fibre dyed before being spun retains its colour better.
Fleeced – dishonestly stripped of money or goods, as with a sheep shorn of its precious fleece.
Spin a yarn – tell a tall story, such as those shared by groups of women working spinning wheels.
Shoddy – of poor quality, from the name given to the inferior cloth made by mixing shredded old rags with new wool.
Run of the mill - regular mill production, not out of the ordinary.