You know I’m a stickler for us designers empowering ourselves with amazing knowledge so we can design smarter and better – well, did you know that most plaids are four-harness weaves? If you didn’t know that then you must read on!
You really need to start by understanding the basic principles of weaving. As you’ll discover in the last article I wrote, weaving is done by interlacing the threads of the warp with those of the weft. What do you won’t find in that article, is that harness looms can be categorised into two different “shedding” methods:
- Rising shed: Any one harness or combination of harnesses was lifted while the other harnesses remained stationary. Examples include the table loom, dobby loom or the Jack loom.
- Lowering shed: Some harnesses are raised while others are lowered, lessening the effort of lifting the selected harnesses because they don’t need to be raised as high as in Rising Shed looms. Counterbalanced looms are lowering shed looms.
N.b. The “shed” on a loom is the space between the heddles (refer to the image further below if you need to jog your memory!).
Professional Weaving Drafts
Here’s a really helpful diagram from Penelope Walton Roger’s book, A brief guide to the cataloguing of archaeological textiles. On the right (the bit that looks like a checkers board) is a professional weaving draft! A black square is called a “float” and a white square is called a “taken“. A float shows where a weft thread goes over a warp thread. A taken shows where the weft thread goes under the warp thread.
This diagram illustrates how a plain weave fabric or a “tabby” fabric is woven.
Two Harness Weave – Aka Weaving With Two Harnesses.
Weaving can be done with two harnesses or “shafts” (have a look at the image below for the part of the loom I’m talking about). The shaft or harness is the frame of the loom that holds the warp threads. These shafts can be moved up or down by “treadles” to allow the weft to cross through and create the desired pattern. The more the number of harnesses, the more patterns you can create.
On a loom with two harnesses set up, one harness carries the odd numbers and the other harness carries the even numbers of threads. The harnesses are raised one after the other, and the shuttle passed through. Examples of a two harness weave are pain weaves or tabby weaves. By passing two threads on the first harness and two threads on the second harness and then repeating this you would create a basket weave. You can also create a basket weave by using two shuttles and passing them on the same shed (the space between the heddles).
Here are two drafts to create a basket weave (top) and a half basket weave (bottom) using a two harness loom. Hopefully you can start to see just how the shaft, warp and weft threads are all beginning to come together!
Four Harness Weaving
A four-harness weave not only has a warp and a weft thread, but also a thread that is woven on both diagonals! This four-way method of weaving yields a higher thread count than most other fabrics – so threads can be more tightly packed and the end fabric therefore more durable. And true to form, these fabrics are incredibly durable, drape beautifully and withstand wrinkles.
Just as a two harness weave is created using two harnesses, a four harness weave has four harnesses that hold heddles (through which the warp threaded are threaded) and may be raised or lowered by means of hand or foot treadles to open or close a shed to pass the weft threads through. The more harnesses a loom has, the more complex a fabric structure may be woven on it.
Interestingly, a four harness loom can still be used to weave plain weave structures, where the first and third harnesses are raised and lowered in opposition to the second and fourth harnesses. Most notably, however, the four harness weave can be used to weave plaids and twills. This is done by raising or lowering only one harness at a time – this method can vary depending on which type of loom is being used, and whether a shed is raised or lowered to be opened. You can do significantly more complex weaving patterns the more harnesses a loom has.
Along my research travels, I came across this astonishing blog Evas Weaving, which I insist you check out if you’re interested in learning more! She showcases some of the drafts she’s created herself alongside the final products she’s woven herself – crepe weave scarves made out of Tencel – right up my street!! As her newest, biggest fan, I immediately got in touch with her and to my groupie joy, she responded:
I really enjoyed reading “Weaving: What are Looms?” I weave on a 16-shaft Macomber treadle loom, similar to the 8-shaft jack-type loom that you show in the first photo with all the parts. I often push my loom’s limits to weave patterns that are usually woven on compu-dobby looms by most handweavers.
I’m delighted that you want to add a link to my blog in your article. My home page is the best link and people can browse through what interests them the most.
It’s an incredibly fascinating process and Eva documents it all beautifully, so please do have a look!