| Giving Weight to your Project |
Marcy Petrini
December, 2023
Throughout this month I have been working on organizing Roc Day, the celebration of spinners returning to our crafts. This year my guild, the Chimneyville Weavers and Spinners Guild, is hosting the event for the Gulf state guilds. Even though the traditional Roc Day is January 7th, the day after Epiphany, we always celebrate on the Saturday closest to Roc Day to allow people to travel if they have week-day responsibilities. This coming year it will be January 6, 2024.
The Craftsmen’s Guild of Mississippi is our co-sponsor, and the event will be held at the beautiful Bill Waller Craft Center in Ridgeland, MS with the help of the wonderful CGM staff.
We have goodie bags and every time that our guild hosts, I provide a small card with useful information – that’s the teacher in me. At least I hope it will be useful to others.
This year the information is for weavers. A lot of spinners weave on a variety of looms, so I want to offer a concept that many weavers – or spinners – don’t think about. There will be a card in the goodie bags with the information.
When I am planning a project with a new yarn, I like to think about how much the fabric is going to weigh – not how much yarn I need, that’s in the planning. I am considering the weight of the finished project to compare with other, similar projects.
Since most weavers are familiar with mercerized cotton, I decided to make the comparison using the most common of those cottons. Below is a scarf using 10/2. How does it compare with the other cottons?
My usual scarf is 8” width on the loom, which becomes approximately 7.5” after wet finishing. Generally, the finished length is 60”.
For ease of calculations, I used 8” as the finished width, as it is easier to think in whole numbers.
To obtain the weight of the hypothetical scarves, these were my calculations: (“*” is the multiplication symbol I prefer to use):
8” * sett for twill *60” *2 / 36
The setts I used in the example are those I generally use for twills. The calculation assumes that the fabric is balanced, that is, the picks per inch is the same as the sett; thus, there will be the same amount of warp and weft in the finished fabric. Therefore, I multiplied the warp calculations by 2. Since yarns are listed as yards per oz., I divided by 36 to convert inches to yards.
Here are the results:
|
Yarn |
3/2 |
5/2 |
10/2 |
|
Sett epi |
12 |
18 |
24 |
|
Yards/Ounce |
75 |
130 |
260 |
|
Yarn in scarf |
320 |
480 |
640 |
|
Weight of scarf |
4.3 |
3.7 |
2.5 |
Clearly a scarf with 3/2 cotton is heavier than 10/2. How heavy we want to make a scarf is a matter of preference, but we need to remember that weight effects drape, the lighter the scarf, the more the drape, although fiber is an important component as well.
The other two yarns that I use a lot are 10/2 Tencel™ and 20/2 silk. Tencel™ uses the same yarn count as cotton, so the 10/2 column in the table above applies to Tencel™ as well. However, Tencel™ is slicker, I like its drape better for scarves. It also has more luminosity, reflecting the light well. Below is a scarf with Tencel™ for warp and weft.
Silk has even more drape and luminosity than Tencel™. I like 20/2 silk, which is close in size to 10/2 cotton. I usually sett it at 24 epi for a twill, even though it has fewer yards per oz., 233 as opposed to the 260 in the table above. With the same sett and dimension the scarf in silk weights 2.7 oz, rather than the 2.5 for 10/2. The silk, however, drapes beautifully. Below is a silk scarf.
The weight calculation is approximate. Small differences can affect the results: slightly different dimensions, beat and sett not identical, and fringes from the warp. The comparison, however, is still useful.
In particular, however, it is important to remember that the yarn, not the heddle or reed determine the sett. I have a rigid heddle with 12 dent, I don’t sett every yarn at 12. If the sett is too open, the weft tends to pack in and results in a weft-dominant structure. The extra weft can increase the weight of the fabric by as much as 50% above that of a balanced cloth.
Once I am satisfied with my yarn choice, I proceed to the usual calculations to determine how much yarn I need for the project.
Next time you decide to use a new yarn, do a quick calculation, and check how the weight compares with other fabrics and whether that yarn is the best option for the project.
Happy Weaving and Happy Creative 2024!
Marcy
| My Inspirations |
Marcy Petrini
November, 2023
Were you inspired by my images?
The pictures I showed in my October blog were taken on a whim. Something caught my imagination. Later I see those images appear in my weaving. Sometimes it’s months later and sometimes the same picture will inspire more than one piece over the course of time.
Here are the pieces I wove inspired by those images, in no particular order.
This is our yard, my husband is the gardener in our family. There are steps that are barely visible in the back and there also steps to the side. I like to “step through the garden”, which is what I called the shawl. The light that filters through the trees appears as a lighter stripe in the shawl.
I love how the purple and red mingle in this sunset, taken just north of Jackson during a guild retreat. I tried to catch the luminosity of the sunset in this ruana that uses clasped wefts with a mohair and wool blend in red and red purple. We generally don’t think of mohair as having luster, but it does.
Many puffy clouds in this Western sky, photographed from the car on the way to Convergence® in Reno. I tried to capture the irregular clouds with the corkscrew twill in this scarf.
I love fall colors. They appear over and over in my weaving. The scarf captures the gold and brown from the tree, but also the intersections of the branches in the twill. The silk lights up the scarf just as light brightens the tree.
Not all inspirations are joyful. Our little RT was killed by a reckless driver. He was affectionate but also adventuresome. Everyone in the family received a fuzzy and soft RT scarf in white, grey and black to remember him.
How do your inspirations compare with mine?
Join me at Convergence® as we explore our inspirations!
Happy Weaving and Happy Thanksgiving!
Marcy
Marcy
| Just When I Thought that I Understood Selvages….. |
Marcy Petrini
September, 2023
For a long time, when weaving basket weave on four shafts, I use two shafts for the basket weave and I leave two shafts for the plain weave, so I don’t have to use floating selvages.
Below is the drawdown followed by the fabric. As for the floating selvages, the plain weave edges must be tensioned separately because the take-up is different.
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I carried that idea to my work when I started using more shafts, if the design would allow it. Below is a shawl with a 38-shaft plaited twill that uses two shafts for the plain weave selvage.
More recently I noted that on twills some weavers used basketweave on the selvages rather than plain weave. Regretfully I forgotten where I saw it (a past Convergence®, maybe, where all the events blend together and are blurred?) It makes sense since basket weave has the floats lacking in plain weave. I promised myself that I would try it next time I had a chance.
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When I designed an advancing points twill on my 40-shaft AVL, I used 38 shafts for the pattern and 2 for the basket weave. The treadling repeat was 222 steps, so to keep things simpler, I decided to weave half a basket, one pick over two warp threads, with the next pick over the other two warp threads. The results shown here were not stellar. Perhaps a true basket weave treadling would have been better. Or since there is so much plain weave in the background of the motif, plain weave edges would have worked just fine. |
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At the usual viewing distance, the edges of the scarf don’t look too bad, and I will certainly wear the scarf. I love the way the motif goes off the fabric on one side only to pick up on the other side.
The scarf is actually a sample. When sampling I like to have at least two repeats of the threading and of the treadling. With a beat of 24 epi, two treadling repeats of the motif weave 18 – 20”. I figured I may as well make a scarf!
Next, it’s a shawl. The pattern and the edges will be tweaked and hopefully I will have splendid selvages. Stay tuned.
Happy weaving!
Marcy
| Do These Images Inspire You? |
Marcy Petrini
October, 2023
Next summer, at the Wichita Convergence 2024, I will be offering a seminar, “Can We Be Inspired by the Inspiration of Others?” This is leading me to think again about inspiration.
The seminar won’t have the format of this blog, but here is something for you to ponder about inspiration.
These five images have inspired me in the past (none of these images will be used at Convergence®).
Look at each image and ask yourself?
- What does this image lead me to think about?
- If I were to weave a project based on this image, what would it be? What item, what color, what structure, what motifs?
Do a sketch, a drawdown or whatever method to use when trying to capture an inspiration.
Next month, I will show the pieces that resulted in my inspiration from the above images
Happy weaving!
Marcy
| Draw-In and the Tyranny of Small Numbers |
Marcy Petrini
August, 2023
I was wondering whether the various extruded natural fibers (Tencel™, bamboo, etc.) have the same shrinkage. I was looking through the spreadsheets of my weavings, one per project.
Looking for this kind of information is the reason to keep good notes. For every piece I weave, I know the width on the loom, sometimes adjusted to obtain a complete repeat of the pattern; I measure the fabric off the loom; I wet finish it as appropriate for the fiber, and measure after. The last two measurements give me the percent shrinkage.
The first two measurements give me my take-up, as I learn it, or draw-in. Whatever you like to call it, the warp is at a certain width on the loom; with the weft going over and under it, there is a certain amount of loss in the width. This happens also in the length. Because the calculations for the take-up and shrinkage are the result of different processes, I like to keep them separate.
What caught my attention in looking through my files was the variation in the width take-up (or draw-in): 7.4% for the blue and yellow scarf below (which I wrote about in my January blog). Its initial width on loom was 8.1”, adjusted for the pattern repeat.
In contrast, the Swedish lace shawl below had a 35.3” width on the loom, again adjusted for the pattern; its take-up was 4.5%. Granted, both percentages are rather small and acceptable, but somehow, I expected the opposite, as I think it may be a bit harder to allow enough weft in a wider piece to avoid the draw-in.
Was I wrong in my expectations? No, actually, the difference in the percentage is what my husband calls “the tyranny of small numbers.” Making conclusions based on small samples is unreliable, and, in this particular case, the smaller width makes the draw-in look bigger.
Here are the actual widths and calculations:
|
Width adjusted |
Off the loom |
Take Up |
Difference |
|
|
Yellow and blue scarf |
8.1 |
7.5 |
7.4% |
0.6 |
|
Swedish Lace shawl |
35.3 |
33.75 |
4.5% |
1.6 |
My hunch was correct – larger piece, more draw-in, although the comparison is not exactly fair since the structures are different.
I am not drawing any conclusions based on two pieces of weaving! My point is that comparing percentages – and ratios – with relatively small numbers can be deceiving. The smaller difference looks larger because it’s a percentage of a smaller number.
We see this deception in everyday life.
At the ballpark, I have watched batting averages (which are actually ratios) go up and down in what seems an unpredictable way. A 300 batter (0.300 actually) with 100 at-bats, gets a hit, and his average goes up to 307. But if he hadn’t gotten a hit, his batting average would have dropped to 297. Over the course of a season, these fluctuations become much smaller and may be unnoticeable, but I have heard broadcasters talk about these deceiving numbers as if they were reliable.
What about my original reason for digging into my files? I couldn’t arrive at any conclusions because I didn’t have enough pieces woven with one fiber only, since I generally mix fibers.
However, the lesson stands. Looking at the percentages of shrinkage was deceiving, too.
Happy weaving!
Marcy
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