Extra Warp

Extra warp, also known as supplementary warp, is where additional warp ends are inserted and used to create a decorative pattern on top of the ground cloth.

The ground cloth is usually kept simple, such as a plain or twill weave, to enhance the extra warp. This extra warp is woven on separate shafts to the ground cloth so that it can be woven independently to create the decorative pattern without interrupting the ground cloth weave.

The example below shows an extra warp design using 8 shafts. Shafts 1-4 are for the ground cloth while the extra warp is on shafts 5-8. The black extra warp ends are inserted at regular intervals along the width of the warp. 

The extra warp ends have been alternated with the ground cloth ends so that they do not interfere with the ground cloth weave. If the extra warp ends were all put in next to each other the ground cloth may end up having gaps.

The white ground cloth ends are put through the reed at a rate of 30 ends per inch. The extra warp threads are put in as additional threads so the warp is actually threaded at a higher density at these point. This is so the ground cloth remains consistent throughout. It needs to be able to weave a plain weave when the extra warp ends are not being woven in.

As you can see there are two woven structures above. In structure 1 the extra warp threads are floating over the surface of the cloth whereas in structure 2 the threads are woven in to the cloth. I have decided to cut the floating threads away. This will leave the black extra warp ends where they have been woven into the ground cloth creating rectangles. Structure 2 can be woven for fewer picks to create small squares or more picks to create longer rectangles.

The resulting sample is below.


Soft Engineering Exhibition

This afternoon I had a lovely time at the Soft Engineering exhibition and attending the talks at Whitchurch Silk Mill I have been to this exhibition before when it was in Winchester but this time there was the edition of Julie Hedges. The exhibition is all about how textiles can be shaped. This is one of the subjects I love to learn about and experiment with.

Being a weave technician at the University for the Creative Arts in Farnham I was very interested to learn that all of the exhibitors have at one point or another been students or employed by the same university. This is how they got to know each other and are all good friends. It was also very interesting to know that even though they are established makers they still get together to talk about and show each other their work. Being able to bounce ideas off each other seems a very important way for them to develop their ideas. I think sometimes it’s easy to forget that even professionals are still learning, can be unsure about their work and need to discuss what they are doing with someone else.

There were four makers exhibiting:

Alison Ellen

Alison Ellen is a knitter who originally trained in weave. She felt that weave was too restrictive so started experimenting with knit. She is now exploring knitted garments without seams, tops in particular. I was already aware of knitting in rounds and therefore it must be possible to knit certain garments without seams but she does this in such an interesting way using shaping techniques and adding texture. She uses combinations of stitch and varies the number of stitches row by row as well as entrelac and modular knitting techniques to create curves, movement and shaping within her garments.

Anne Richards

I have attended talks by Anne Richards before but always come away inspired and feeling like I have learnt something. Anne Richards originally studied biology and discovered her passion for weave when she started doing this in her spare time.

Now she is known for creating sculptural pieces, particularly necklaces and bracelets. She shapes her weaves mostly by using high twist yarn. High twist yarn have a very high twist count when spun giving it a lot of energy. When it is put on to a cone it settles down making it easier to weave but once it gets wet the fibres swell putting stress on the yarn causing it to shrink up. 

Her three dimensional textiles exploration was inspired by an accident when she accidentally created pleats not actually being aware of how high twist yarns behave at the time. She creates her pleats by playing with warp/weft dominant weaves, S/Z twist yarn and different fibres. By using them in different combinations she can create different effects. She also discovered that if she uses silk/steel yarn she can manually insert some pleats once the fabric is woven.

Some of her designs were inspired by origami mountain and valley folds and the mobius strip. She also cuts/stitches woven fabric together to add a different dimension. She no longer weaves most of her work herself but employs highly skilled weavers to do this for her. Her samples we finished using a folded and stitched edge.

Deirdre Wood

Deirdre Wood studied ceramics and then knit before discovering her love of weave. Having been inspired by the strip weavers around the world she now embraces this technique herself. She loves the strip woven cloths of west Africa, in particular the mud and ikat cloths of Mali. 

Strip woven cloth is created by weaving narrow strips of fabric and stitching them together to create a bigger cloth. Cloth is traditionally made this way due to a lack of resources to be able create larger cloths. There may be no access to a large loom or the finances to buy the quantity of yarn outright before starting weaving. 

Deirdre weave strips and then manipulates, twists and sews them together to create striking designs. She creates some double sided strips for when they are folded back upon themselves. Through experimentation she found that if she graduates the yarn type across the width of the strip e.g. silk to cotton or linen when she washes it the yarn shrink differently causing the strip to curve. It became very mathematical when she decided to work out how long she would need to weave the strips in order to make a full circle. She engaged the help of a computer professor to help. She adds ikat techniques in to her work which she dyes using a collapsible frame she made herself. 

Julie Hedges

I went to this exhibition mostly knowing what to expect but learnt about a new technique I have never heard of, ply-split braiding. Ply-split braiding is essentially where you start off with number of cords which you then commence to thread though the middle of each other. 

Her interest in this techniques was first sparked when she when to an exhibition at the University for the Creative Arts, Farnham in 1989 displaying some of the historic fabrics they hold in their collection. She further learnt about it when she worked at the university and staffed a workshop with Peter Collingwood who was the first westerner to research ply-split braiding in depth. 

During a trip to Rajasthan she became inspired by the camel girths which are made from camel hair using ply-split braiding techniques. Julie likes using four ply linen or cotton cords for her work,  She then uses a grip fid (traditionally used for rope splicing) topull the cords through the middle of each other so that two of the plies are over and two under the cord. Julie often makes her own cords and explores thickness and stiffness to develop her structures, often combining variations. 

There are a number of techniques to create different effects: ply-split darning, single course oblique twining and two layered oblique twining. She quickly realised that she could create 3D shapes which naturally lend themselves to jewellery.  Natural structures provide some inspiration but mostly her next piece is inspired by a previous.


Calculating weft yarn quantity

Once you have decided on a project you may want to work out how much yarn you are going to need. This may be so you can buy or dye the correct amount without vastly over or under estimating.

The following will take you through the calculation to work out how much weft yarn will be needed. It looks like a lot but they should be relatively straight forward things to work out. For the sake of simplicity I will work in centimetres/meters but the same can be applied to inches/yards.

The calculaion is as follows:

Total number of picks x total width of fabric (m) = amount of yarn needed (m)


How to work out the total number of picks

  • PPC (picks per cm) x (length of woven piece (cm) + shrinkage/take-up (cm)) = Total number of picks
    • The picks per cm is usually determined by sampling but if it has no been woven before see CALCULATING A SETT and use the same as the epc.
    • The shrinkage/take-up is usually assumed to be 10% of the width of the woven piece but this can vary by a large amount depending on the yarn, structure and finishing. Sampling will give you a more accurate number.

How to work out the total width of the warp

  • width of woven piece (m)+ shrinkage/take-up (m) = Total widthof warp (m)
    • The shrinkage/take-up is usually assumed to be 10% of the width of the woven piece but this can vary by a large amount depending on the yarn, structure and finishing. Sampling will give you a more accurate number.
    • It is often easier to work out the calculations in cm and then convert to m by dividing by 100 at the end.

As a working example:

Total number of picks:

  • 8 ppcm
  • 200cm length of woven piece
  • 10% of 200cm = 20cm shrinkage/take-up

8 x (200 + 20) = 1760 picks

Total width of warp:

  • 50cm wide woven sample
  • 10% of 50 = 5cm shinkage/take-up

50 + 5 = 55cm (0.55m)

1760 x 0.55 = 968m of yarn needed for the warp

Calculating warp yarn quantity

Calculating the sett


Leno Weave

Leno is a weave structure where two or more warp threads twist around the weft threads. This technique is often used to create strong, fine fabric which is stable. The twisted warp yarns ensure the yarn does not move. It is also useful to use this ta the edge of a gap in the warp otherwise the warp ends have a tendency to want to fill the space.

Setting up a loom for doup leno is time consuming but once it is set up it’s fairly quick to weave.

To create this structure a loop of thread (a doup) is attached to an empty shaft and travels through an empty heddle on an adjacent shaft. The doup warp end is then threaded through the doup to pull it under an adjacent warp end creating a twist. A weft pick holds the twist in place.

Below shows a doup attached to shaft 2 and poking through an empty heddle on shaft 1. Two shafts are needed to create the twist and two are needed for the twisting warp ends. This is in addition to any shafts needed if other structures are to be included in the fabric. It is important that the doup is not too long and only just reaches through the heddle as this would result in a poor shed. The warp end to be twisted will be threaded through this loop rather than a heddle.

 

 

A strong smooth thread works best for the doups. A doup will be needed for every twist required. It’s a good idea to make the doups by tying them around something such as two nails in a piece of wood spaced the required distance apart. They need to all be consistent in length to ensure an even shed.

The direction of the twist can be changed and the number of warp ends which twist around each other can be varied. The following shows a selection of options:

 

 

Here is a draft for a weave using doup leno and plain weave structures:

It is important to remember that all the twisting threads (leno ends and warp ends) must be put through the same dent in the reed.

To make it easy to see which warp ends will be twisting these threads are black. All the other threads are white. 8 shafts are used:

Shaft 1 will contain the empty heddle for each doup to be threaded through and will be lifted every time the warp thread is to be twisted.
Shaft 2 is where the doups will be attached .This shaft will need to be kept raised throughout the whole weaving process otherwise the leno warp end may be broken.
Shaft 3 is for the black leno ends which are the ones to be twisted. This will be lowered when shaft 1 is lifted to create the threads.
Shaft 4 it for the warp end that the black end will twist around and remains stationary (lowered) throughout the weaving process.
Shafts 5-8 are used for the plain weave of the rest of the fabric.

In the draft above there are two sections of Leno on a plain weave fabric. One on the left where just two leno threads are used to stop the warp moving in to a gap in the warp. The second on the right is an area of leno in which two leno ends twist around two warp ends.

Below are close ups of the two different leno weaves from the above draft as well as a diagram for each to show how the dark leno ends are twisitng.

 

 

          

 

 

          


Extra Weft

In an extra weft structure one weft yarn is used to weave a ground cloth and an additional weft is inserted at intervals to create a decorative pattern on the surface on the cloth.

The ground cloth is usually woven with a simple structure such as a plain or twill weave to enhance the extra weft but other structures can be used.

The sections of the warp that will interact with the extra warp to create the pattern are set up on separate shafts to allow it to be woven independently from the ground cloth where required. The number of shafts needed depends on how complicated the pattern is going to be.

For the example below I have used an eight shaft loom. Plain weave is woven across all 8 shafts for the ground cloth (block A and B woven simultaneously). Shafts 5-8 (block B) are only threaded in specific areas and are woven independently to create diamonds at regular intervals throughout the cloth.

The first end in block A after a block of B must be threaded on shaft  two otherwise a plain weave structure will not be possible. The best way to spot these potential errors before weaving is to draw out the draft either by hand or on a weave program.

Below is the weave draft showing how a diamond structure can be achieved using an extra weft structure:

To ensure a stable structure around the extra weft diamond, the ground cloth picks are alternated with the extra weft picks. On the left of the draft the filled circles represent the extra weft and the empty one the weft represent the ground cloth.

This is how the blocks will be spread throughout the woven sample:

Where there are three diamonds placed right next to each other I have placed one warp end separating them, threaded on shaft two. If they were not separated by this thread there would be one weft pick floating over the middle of all three diamonds. Threading plan for the three diamonds next to each other:

The woven samples below are all woven with the same warp set up. Included is the diamond structure explained above.

Extra weft structures can be used in many different ways to create a vast range of cloths.


Calculating warp yarn quantity

Once you have decided on a project you may want to work out how much yarn you are going to need. This may be so you can buy or dye the correct amount without vastly over or under estimating.

The following will take you through the calculation to do this. It looks like a lot but they should be relatively straight forward things to work out. For the sake of simplicity I will work in centimetres/meters but the same can be applied to inches/yards.

The calculaion is as follows:

Total number of ends x total length of warp (m) = amount of yarn needed (m)

How to work out the total number of ends

  • EPC (see calculating sett) x (width of woven piece (cm) + shrinkage/take-up (cm)) = Total number of ends
    • The shrinkage/take-up is usually assumed to be 10% of the width of the woven piece but this can vary by a large amount depending on the yarn, structure and finishing. Sampling will give you a more accurate number.

How to work out the total length of the warp

  • Length of woven piece(s) (m)+ shrinkage/take-up (m) + yarn wastage (m) = Total length of warp (m)
    • If weaving more than one piece add the lengths together
    • The shrinkage/take-up is usually assumed to be 10% of the length of the woven piece but this can vary by a large amount depending on the yarn, structure and finishing. Sampling will give you a more accurate number.
    • Yarn wastage is the amount of yarn used to tie on to the front beam plus the warp woven for even end distribution plus the loom waste (the amount of yarn left on the loom not able to be woven).
    • It is often easier to work out the calculations in cm and then convert to m by dividing by 100 at the end.

 

As a working example:

Total number of ends:

  • 8 EPC
  • 50cm wide warp
  • 10% of 50cm = 5cm shrinkage/take-up

8 x (50 + 5) = 440 ends

Total length of warp:

  • Three 50cm woven pieces = 150cm
  • 10% of 150 = 15cm shinkage/take-up
  • 10cm to tie on
  • 5cm to weave distributing picks
  • 50cm left on the loom that cant be woven

150 + 15 + 10 + 5 + 50 = 228cm (2.28m)

440 x 2.28 = 1003.2m of yarn needed for the warp

Calculating the sett