From Four to More

Marcy Petrini

5/2/2016

In last week’s blog I mentioned that I like to think of two methods for extending weaving structures from four to eight shafts; one way is to simply extend the threading; the other way is to divide the eight shafts into two sets, which I call the “front” loom (1, 2, 3, 4) and the “back” loom (5, 6, 7, 8).

The methods are not clear cut, but they have helped my students use those extra shafts. Surveys have shown that weavers buy eight shaft looms, but often just use four, perhaps because there can be some difficulties – namely floats – that have to be solved with the extension.

We can apply the two methods to overshot and monks’ belts. For a simple extension to eight shafts, the four-blocks of overshot listed last week become:

The process works for threading, but the treadling presents the float difficulty. Look at the drawdown below where the blocks were woven one at a time, as it is done in 4-shaft overshot. This is for a sinking shed loom. As in four shafts, when we weave one block, shown in yellow weft here, we obtain half tones in the two adjacent blocks; the problem becomes that there are five blocks remaining; the solid red represents areas of plain weave, since the drawdown only shows the pattern weft; but wherever plain weave appears on this side of the cloth, there will be weft floats on the other. Treadling a single block produces continuous floats over five blocks (right click to open a larger image in a new tab).

The solution is to break up the blocks in the threading, or combine blocks in the treadling, or vary the size of the blocks, or a combination of these.

For monks’ belts, we can use the idea of a front and back loom; these are the blocks:

Then in treadling, we have to weave the front and back looms at the same time. We already know from four shafts that only one block at a time can be woven because of the floats, with two looms, we can have four possible combinations: block A with either C or D; and block B with either C or D.

However, the float problem persists, but not as extensive as in overshot: there are two combinations that are viable. Look at the drawdown below, also for a sinking shed loom. The orange represents areas of weft floats; whenever the floats are over two blocks, they are too long. The blue represents areas of plain weave, which, however, are floats on the other side of the fabric. Thus, for this threading, A & C, and B & D produce reasonable floats.

In this case, using the front and back loom idea helped us eliminate some floats. If we had extended the threading for monks’ belts as we did in overshot, we would have started weaving one block at a time, and it would have taken us longer to arrive at the combinations that work.

This front-and-back-loom method works particularly well when we want to combine structures. We could weave a twill in the front loom and huck in the back loom. Even without extending the threading, the possibilities are staggering.

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What's in a name?

Marcy Petrini

4/25/2016

I find it very confusing when people use the incorrect terminology to describe an entity. My husband Terry Dwyer always says that the vocabulary in any given field is a good part of learning that discipline, be it medicine or weaving. And my advisor in graduate school would always insist on not changing the meaning of a word for our convenience, or even inventing one when there was a perfectly good term already available. Perhaps that is the reason why redefining terms drives me crazy, whether it’s the “crab cake” made with tofu and herbs in a menu, or the description of the natural media of “wood, paper, plastic, and graphite” used by a New Orleans artist, or color-and-weave as we talked about in my April 11, 2016 blog; what’s wrong with tofu cakes? Or man-made plastic as an art medium? Or a colorful twill scarf? The more exact we are with our vocabulary, the clearer the information we are trying to convey.

Unfortunately, there are ambiguities, especially when we use more than four shafts, although last week (blog of April 25, 2016), we talked about shadow weave on four shafts appearing in two ways just by changing the order of the colors in the treadling: as a weaving structure shadowed, or as totally different color-and-weave motifs.

Another ambiguity that I have run across is overshot and monks’ belts. Both structures are supplementary weft weaves, with a pattern weft, loftier and larger than the ground warp and weft, which forms blocks superimposed to the ground cloth. Below is a sample of overshot with its characteristics three areas: the overshot area, the blue blocks in this sample; the plain weave area, in white; and the half-tones, showing grids of blue and white.

Whenever a block appears on one side of the fabric, there is plain weave on the other, and vice versa. The half-tone areas are formed by the sharing of shafts between blocks which are derived from twills: block A is threaded 1, 2, repeat; block B is threaded 2, 3 repeat; block C is threaded 3, 4, repeat; and block D is treaded 4, 1, repeat.

In contrast, monks’ belts, shown below, has no half tone areas, because there is no sharing of shafts between blocks; while overshot has four possible blocks on four shafts, because of the sharing, monks’ belts has only two: block A is 1, 2, repeat; block b is 3, 4, repeat.

Is monks’ belts just a variation of overshot? It has been called overshot on opposite (since block B is threaded with the opposite shafts of block A). Or is it its own weaving structure since it lacks the half tones which are characteristic of overshot?

When we move from four shafts to eight shafts, another complication arises that adds to this confusion: floats. Do you see why?

How overshot and monks’ belts are extended from four to eight shafts are examples of the two methods that I like to think can be used for this extension. This is a topic that I will discuss at the More Than Four super seminar at Convergence^®, and there will be a brief introduction in my next blog.

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Shadow Weave

Marcy Petrini

4/18/2016

Is Shadow Weave Color and Weave? It is generally considered so, but in my mind there are two types of shadow weave. How we obtain them is so closely related that we generally don’t make the distinction. 

In the first type, shadow weave does what its name implies: a shadow follows the main structure. Look at the drawdown below: the weave is rosepath and you can see the diamond outline and its shadow.  (Right click and open in a new tab to see a larger view.)

Some shadow weaves show even more pronounced shadows, but I have a reason for choosing this particular draft, which is the other type of shadow weave: the one that I consider a true color and weave. Look at the drawdown below:  

The threading and the treadling are identical to the previous draft; the only thing that has changed is the color order! But gone are the rosepath and its shadow! The resulting motifs are unique, although in some parts the dark shadows the light, or a better way of saying is that the dark outlines the light, which in turn outlines the dark…. 

This draft comes from Marian Powell’s book 1000 (+) Patterns in 4, 6, and 8 Shadow Weaves which was published in 1976. She developed a method to look at shadow weave that is different than the previous way described by Mary Meigs Atwater. However, the two methods produce the same results. Powell follows the threading of the structure so it’s easier to thread, I believe. 

This warp is going on the loom next, so soon I will have these two samples for show and tell. Stay tuned…. 

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Color and Weave

Marcy Petrini

4/11/2016

One of the seminars I am scheduled to teach at Convergence® is Color and Weave; summer is just around the corner and I am spending a lot of my time weaving samples and writing the handout – and thoroughly enjoying it!

Color and Weave motifs are optical illusions, we don’t see the underlying structure and we don’t realize the threading color order.

Here is a quiz about Color and Weave: what’s the difference between these two fabrics (besides the colors)?

Yes, the blocks are different sizes, but there is another striking difference; look at the drawdowns:

Both are the color and weave pattern called log cabin. As you can see from the drawdowns, only two shafts are needed. Sometimes log cabin is woven using basket weave, but still, two shafts are sufficient to obtain the horizontal and vertical stripes. Two colors alternate in the threading and the treadling; to switch the direction of the stripes, the colors are changed both in the threading and in the treadling.

And here is the difference: the red and black fabric and drawdown on the left have each block of stripes framed by the same color, in this case red. Note that at the end of the horizontal stripes, in the threading a red thread on shaft 1 is followed by a red thread on 2; similarly, to switch back from vertical stripes to horizontal stripes, the red thread on shaft 2 is followed by a red thread on shaft 1. We could have framed the blocks using black in the same manner.

In contrast, in the black and white fabric and drawdown on the right, the color changes vary. The first switch is like the black and red fabric: a white thread on shaft 1 is followed by a white thread on shaft 2, so the stripes change from vertical to horizontal. At the end of the vertical striped block, however, the switch occurs on the black: a black thread on 1 is followed by a black thread on 2. The blocks are no longer framed, and they seem a bit lopsided in the drawdown, but the fabric seems to move!

What do you prefer: framed blocks or moving blocks? The choice is yours, but now you know how to obtain whatever ones you prefer.

For more on color and weave, see my article in Shuttle Spindle & Dyepot, “Right from the Start: What Makes a Fabric Color-and-Weave?” in the summer 2015 issue. Or better yet, take my seminar at Convergence®! 

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