Flowing Curves: Network Drafted Twill

by Bonnie Inouye on August 28, 2009

My previous curves article explained how to create smooth and flowing curves using the overshot weave structure. In this second installment, we look at designing curves in the treadling using network-drafted twills.

Curves can be created by repeating a pattern treadle, as seen in many undulating twill drafts, but this causes areas of tight interlacement combined with more open weave in the same cloth.

I prefer a consistent interlacement. It creates a consistent drape, preventing sagging areas—an important consideration if you intend to sew with the fabric. Consistent interlacement also ensures the fabric wears evenly; an area with longer floats will abrade faster than an area with short floats. In addition, a consistent look to the surface of the cloth focuses attention on the design instead of the cloth's structure. Network drafting is a method for creating a weaving draft to express your design in the consistent structure of your choice. It's powerful and fun.

I have certain goals for each warp: I choose fiber and colors appropriate for the intended cloth, and plan a series of items because it is most efficient to warp several yards at a time.

When choosing a weave structure, I consider many factors: Which structure gives the hand and drape I want? How heavy should this fabric be? Is light reflectance important? I consider durability, float length, and the possibility of textured fabric. Does it need to be warm? Elegant? Do I want woven iridescence? Should my design look neat and crisp or are soft edges all right? (Soft, shaded designs come from overlapping blocks and clear design edges come from units.) Do I want to include curves? (Smooth curves come from using more pattern blocks, while unit weaves generally have fewer than the maximum number of pattern blocks. The more shafts on the loom, the less important it is to use as many blocks as possible for curves.) I look for a structure or a method that gives the results I want for the warp I am planning. I study the way this structure works and see if I can make it do what I want.

fabric detail Twill is a well-known structure that produces a nice handle, drape, and durability. For a warp of 20/2 dyed silk, I decided to weave twills. I envisioned scarves with smooth flowing curves like a meandering river.

I want the curves to flow up and down the scarf, not across it. This means that the curves need to come from the treadling sequence. My threading sequence follows a diagonal progression from one threading block to the next because any reversal of direction will make the curves reflect back.

First I considered an advancing twill. For 8 shafts, I like a 5-end advancing twill (1-2-3-4-5, 2-3-4-5-6, etc) because the space between the twill lines is the same as the spacing of a 4-shaft twill. With this threading, I can weave a flawless 4-shaft twill.

5-end advancing twill threading on 8 shafts, 40 ends per repeat
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Advancing twill would work well, but I had another idea. For curves like water, I like to use advancing points because the resulting shapes remind me of sunlight hitting the surface of the stream. I compared several sizes of points and decided to advance a point that starts 1-2-3-4-5-6-5-4-3. The next point starts on shaft 2 and is the same size as the first. Either of these threadings would be appropriate for a meandering stream design in a scarf, so I looked at both options side-by-side using weaving software.

An advancing point threading for 8 shafts with 72 ends per repeat

Advancing a sequence is a way to get a diagonal progression. Although advancing points are not part of network drafting, this threading does work with network-drafted twill treadlings because I can weave an appropriate underlying 4-shaft twill with it. However, my choice of points in the threading will give me longer weft floats on my scarves. The preceding advancing twill threading causes three-thread weft floats if there are three adjacent shafts rising or sinking in the tie-up. Changing to an advancing point threading creates five-thread weft floats with those tie-ups.

I am using a sett of 30 epi, however, so 5-thread weft floats are not a problem. My yarns have some sheen. This luster is highlighted by a structure with slightly longer floats. For consistency, I want those floats to be evenly distributed across the fabric; an occasional, isolated longer float would stand out and draw attention away from my curved design.

The reason to use network drafting is because it provides consistent interlacement. I know how to maintain the plain-weave ground structure for overshot, by alternating odd-numbered and even-numbered shafts in the threading and then weaving with tabbies. Using network drafting, I can figure out how to maintain any underlying structure. I am fortunate to have references and weaving software to make it easier, but the concept is not difficult. My treadling sequence needs to conform to the spacing that allows my chosen structure, here a 4-shaft twill, as seen in the 5-end advancing twill threading. I want to weave flowing curves with the drape and float length of a 4-shaft twill treadling woven on a point threading. I want the design to show from a distance so I have chosen a threading with a relatively large repeat, 72 ends on an 8-shaft draft, a repeat of about two and a half inches at 30 epi. When creating a new design, I always consider the scale of the finished cloth.

To make a curve, I start with a diagonal line and then change the slope of the line, as described in Flowing Curves: Overshot and Weaving as Overshot. The 5-end advancing twill gives me a diagonal line of twills which meets my requirements for the base cloth. For my tie-up, I choose a 3/1/1/3 twill because it gives me maximum contrast while conforming to the 4-shaft twills needed. I read these numbers on the first treadle, which shows 3 black squares, 1 white (making a 3/1 twill) and then one black and three white (1/3 twill). This is the way twill tie-ups are named.

Diagonal design, 5-end twill treadling, 8 shafts
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I want to increase the length of one of these treadling blocks while maintaining the base of a 4-shaft twill (known as an initial of 4 in the literature on network drafting.) It takes four picks to maintain the structure so I repeat the last four picks of a twill run.

Adding runs of 4 picks to the previous 5-end advancing twill treadling
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I see the curve more easily when I zoom out. I compare these two threading options with the treadling shown above, using two repeats of each threading to make sure the lines will continue smoothly across the fabric. See how the advancing twill threading maintains a consistent twill structure with parallel diagonal lines, while the points give an overall base of zigzags coming from the threading? This draft also shows the difference in scale between the 5-end advancing twill with a repeat of 40 ends and the advancing point with a repeat of 72 ends. I design curves to fit the threading that is on the loom. This comes naturally when I am designing at the loom and watching the cloth grow.

Distance view of preceding draft, two repeats of each threading

I can add repeated runs of 4 picks whereever I want more length. This gives me a way to make a more gradual, longer line. It is all I need to create undulating lines, but I also want curves that meander back, like a C or an S.

I still want to maintain the consistent interlacement of the base structure, so I need some rules or guidelines. The essential requirement for the draft is that I maintain the consistent white space between the twill lines. When I am sitting at the loom, I can literally feel that white space as the distance between the treadles. I want to help you share in the fun of weaving curves and designing at the loom (or on graph paper or a computer).

How to improvise a network-drafted twill design at your loom using 8 shafts and 8 treadles

Start with the tie-up given here, 3/1/1/3. Use a weft yarn that is not the same value as your warp yarn. This means that it provides contrast because it is either darker or lighter than your warp. A strong value contrast makes it easier to see the results of your treadling changes in the cloth.

Weave using each treadle once, 1-2-3-4-5-6-7-8, to check that the tie-up is correct and see the direction of the diagonal line. With a straight draw threading, this diagonal should be close to a 45-degree angle. With a longer threading repeat like those pictured here, it will almost be a horizontal line because the diagonal is going across a design rectangle 72 ends wide (or 40 with the advancing twill threading) and only 8 picks tall.

The next move in a twill order after treadle number 8 is treadle number 1. It is important to remember that after the last treadle, the first one is next.

You always have two choices with network drafted twill (initial 4) on an 8-shaft loom. One option is easy. You can move your foot to the next treadle, meaning the next one in the twill sequence. Usually this means that you move one place to the right (except when moving from 8 to 1). But if you always take this option, you can see that the resulting treadling is very short and will not curve.

The other option is to move your foot to the left, always using the correct spacing. Say you have just used treadle number 8, so your foot is still on this treadle. Move it to the left and feel the treadles. The other option is treadle number 5, which you know because you can always repeat the last four picks, in this case 5-6-7-8. This makes sense because you know that you can weave 4-shaft twill using those four treadles, especially if you have woven twill blocks on 8 shafts.

Now your foot is on treadle number 8 and you want to move to number 5 without looking down. Move to the left: not 7, not 6, yes 5. When I do this, I think "no, no, yes". Resume weaving with a pick on the "yes" treadle, then another pick on the next treadle to the right. Generally it is good to weave at least two picks in order (two consecutive picks moving to the right) because a single pick is hard to see.

no, no, yes

Creating a Design

The more picks you weave in consecutive order to the right, the closer you get to an almost horizontal design line. This is what you saw when you started with eight picks in a twill sequence.

If you repeat the last four picks, you change the slope of the line. It looks more vertical because it is a longer treadling sequence. Look at the 5-end advancing twill sequence at the beginning of this article. You can get this treadling sequence by weaving five picks using treadles 1-2-3-4-5, then moving back "no, no, yes". Starting on treadle 2, weave five more picks, move back "no, no, yes" again, etc. If you always use the same number of picks in each twill run, your design will be a diagonal line. You can make a straight diagonal line with a longer sequence by adding another run of four picks. This is called an expanded advancing twill. Begin with 1-2-3-4, (back not 3, not 2) 1-2-3-4-5, (not 4, not 3). Then weave 2-3-4-5 (not 4, not 3) 2-3-4-5-6.

If you repeat the last four picks many times, you create a vertical line. It is related to weaving 8-shaft twill blocks.

Treadling includes a repeated run of 4 picks: 5-6-7-8 is repeated several times
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With the given tie-up, you can see that a line going to the right in the treadling creates a line going left in the drawdown and on the cloth. If you find this confusing, you can change the diagonal in the tie-up.

So far, all of these designs have progressed in the same direction. How can you make the line curve back? It is tempting to reverse the treadling sequence shown, but that will make a reversal of the little twill lines in the cloth. At the point of reversal, there will be a five-thread warp float, the only warp float longer than three. Both the longer float and the reversing diagonal lines will make a strong straight horizontal line in the design. This will draw your eye and distract from the movement of the design. And it would no longer be a consistent interlacement! Instead, stick with the ground rules: your foot can either move to the "easy" next treadle to the right, or it can move "no, no, yes" to the other option.

This is how it works:

If you weave 5 or more picks in sequence, the line moves to the left with the tie-up given.
If you weave 4 picks in sequence and repeat them, the line stays in place. It does not move to the right or to the left.
If you weave fewer than 4 picks in sequence, the line moves the other way!
You can always add 4 picks to keep the line from moving too quickly.
Always maintain the spacing: next treadle to the right or move back (left) "no, no, yes".

Curves with a C shape
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Practice designing curves and it will get easier to make graceful curves. I learned that curves often look more natural if I make them quite broad at the center of the curve, adding more runs of four than I would have guessed were needed.

Even if you have more than 8 shafts, you can use these same rules as above. And if you have a loom with dobby bars and pegs, you can peg only the tie-up and move the bars forward, then back "no, no, yes". This is how I figured out my system for designing at the loom.

With more than 8 shafts, there are more options that will give you the same consistent interlacement but a different design. If the first four picks are on treadles 1-2-3-4, the next one can be on 1 or 5 or 9 or 13, etc. But if your design is a flowing curve, your logical options are those same two choices: either the next one in order, or move back "no, no, yes".

There is one more rule: only the pattern treadles count. If you have tied two treadles for tabbies, remember to skip those when moving to the right or the left, and also avoid stepping on the brake by mistake!

Draft for scarf with red silk warp and dark purple weft
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Same draft, zoomed in to show the treadling

An advancing-point threading sequence may be stopped at the end of any point. There is no need to stick with multiples of 72 ends for this particular threading. I used 240 ends for a rather narrow scarf (eight inches in width at 30 ends per inch.)

You may follow this treadling sequence and repeat it to learn about making curves. But I think it is more fun to make up new curves, whether you design at the loom or on weaving software or with graph paper.

Curves on More or Less than Eight Shafts

The preceding examples show how to design network-drafted curves on eight shafts, but you can of course create curves using more or less than 8 shafts.

Consider what happens if we take the scarf curve design above and reduce it to a 6-shaft pattern. The draft below shows a network-drafted twill with an initial of 3, the underlying structure being a 3-shaft twill.

To design at the loom for a 3-shaft twill, move to the next treadle to the right or move your foot back sing "no, yes". If you weave 4 or more picks in sequence, the line moves to the left. Weave 3 picks and repeat them to stay in place. Weave 2 picks in sequence and the line moves to the right. Add 3 picks for more gentle movement.

Scarf draft, expressed as a 6-shaft draft
Download draft as WIF file scarf as 6-shaft draft

You can even create network-drafted twill curves on 4 shafts. This 4-shaft draft shows the use of 3-shaft twills on a 4-shaft loom. I wrote an article on this for Weaver's magazine which was republished in the book, Best of Weavers: Twill Thrills.

Network-drafted twill curve on 4 shafts
Download draft as WIF file 4-shaft curve

You can also go the other direction with your design and add more shafts for a smoother curve. Consider the scarf curve woven on 16 shafts. Below is a 16-shaft version with a tie-up that I like. This can be woven with 16 bars on a dobby loom or 16 treadles on a traditional floor loom. The curves look more stretched because the threading is twice as wide, but you know how to change the shape of any curve. I hope you have fun with this!

Scarf draft, expressed as a 16-shaft draft
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References

Alice Schlein, Network Drafting: An Introduction, 1994 available through the author's website.
Weaver's magazine, articles by Alice Schlein and others.
Twill Thrills: The Best of Weaver's. My articles on advancing twill and network drafted twill are included in this book.
Bonnie Inouye, Exploring Multishaft Design, 2000, chapter 5. This book is available from the author's website.
Drafts for this article were created using Fiberworks PCW.
Bonnie Inouye's WeaveCast interview, 28: Designing Multishaft Drafts

Bonnie Inouye has been weaving since 1967. Her award-winning work is characterized by flowing lines, intriguing textures, and bold images. She enjoys using weaving software to create innovative drafts for her sixteen- and twenty-four-shaft looms. Bonnie has taught in nine countries and authored many weaving articles as well as the book, Exploring Multishaft Design. You can hear her talk about her work on WeaveCast 28: Designing Multishaft Drafts. To learn more about Bonnie and view a gallery of her work, visit her website.