There are many sources to find out about weaving drafts and how to read them – however most of what I’ve found is either for multi shaft looms (e.g. check out joy of weaving, Cally Booker on floor looms and table looms, or Peggy Osterkamp) or for rigid heddle looms (joy of weaving again). I thought I might save you some time if I combined the two in a single place.
So, what is a draft? As a starter on a rigid heddle loom, I came across the term “draft” or “weaving draft” very often, and wondered what it was (though I could weave quite happily without needing to know anything about it).
It may be useful to think first of the basics of a loom.
Most loom types seem a variation of the following: a more or less rectangular frame that keeps a set of threads, which are said to form the warp, in tension. Then another set of threads, called the weft, are interlaced with the warp, by being woven at a right angle across the warp, with each weft thread going over and under the weft threads. The way in which you go over and under determines the pattern.
You could weave with a needle – in fact, tapestry weaving uses exactly that. it is slow, though, and so heddles come quite handy: if each warp thread goes through a heddle, then by lifting heddles you lift a certain group of threads, and so rather than slogging a needle up and down what could be very many and very fine wapr threads, you lift all those threads you should go under, create a shed (i.e. an opening) between the lifted threads and those that stay put, and can pass the weft thread through with a “big needle”, i.e. a shuttle. In some looms (e.g. a rigid heddle loom) you can also lower heddles, in others (e.g. countermarch looms) you lift some heddles and lower the others at the same time. In all cases the objective is to create a shed as tall as possible to put the weft thread comfortably through.
How to do all this lifting (and lowering) of heddles? You need a “shaft”, something that the heddle is secured to which can pull it comfortably up and down. To do any weaving you need at least two shafts, so that you can lift different groups of threads to get warp and weft interlacement. In a rigid heddle loom you would have some threads in a slot and some in the hole: by lifting the heddle you are raising the threads in the holes – call these “shaft 1”. By lowering the heddle, you push down the warp threads in the holes, so that those through the slots are raised relative to those in the holes – call these as “shaft 2”.
A “draft” then is a plan that tells you which warp threads go through which heddle (the draft threading) and which set of heddles, hence which shaft, has to be raised at each pick (the draft treadling). It may be that your draft wants you to manipulate some shafts at the same time, or separately. This is noted in the tie-up section of a draft.
The combination of threading and treading will produce a specific warp and weft interlacement, the drawdown.
For plain weave only two shafts are needed, i.e. shafts 1 and 2, and in the treadling you shafts 1 and 2 are lifted in alternating fashion. In a rigid heddle loom, a single heddle behaves as two shafts, where e.g. call the holes “shaft 1” and the slots “shaft 2”.
Below is a plain weave draft. In the threading each column corresponds to a warp thread and each row refers to a shaft (start counting from the bottom). In the treadling each row corresponds to a weft thread, and each column refers to a shaft. In the box occupying the right top corner, each row corresponds to a shaft. Finally each solid black box indicates a thread/shaft combination.
Start from the tie up: the bottom corner identifies shaft 1, and the top corner identifies shaft 2.
Next, the threading: the bottom row links up with shaft 1 of the tie up, hence it tells you that the odd warp threads go through heddles in shaft 1 (or holes in a rigid heddle); while the top row links up with shaft 2, so it tells you that the even numbered threads go through heddles in shaft 2 (or slots in a rigid heddle).
Finally, the treadling, the first row tells you that at the first pick you should lift shaft 1, since the first solid box corresponds to shaft 1; the second row tells you to lift shaft 2, as the second solix box corresponds to shaft 2. The third row is again a pick with shaft 1 lifted, and so on. With a rigid heddle loom, lifting shaft 1 would mean put the heddle in the up position, and lifting shaft 2 would mean put the heddle in the low position.
No drawdown shows in the pictures above. To think how it should look like: the first bit of the treading says to lift shaft 1 when passing the first weft thread (i.e. weaving the first “pick“). This means that all odd warp threads will be up, and all even threads will be down – hence the weft will go over all even threads, covering them. With a rigid heddle loom, the first pick would mean raising all the threads through a hole, so the even threads in a slot will stay down.
Then with purple weft and white warp, after the first pick the project would look this:
The second pick tells you to lift shaft 2/put the rigid heddle in the down position, hence after the second pick you have this:
and so on:
This is the simplest draft there is! Of course a draft could use more shafts, and the treadling could prescribe lifting multiple shafts at a time – for instance in 2/2 twill shafts are always lifted in pairs, here is an example:
The pictures above are screenshot from weaving software, which makes experimenting very easy, and hours fly by quickly playing around with drafts. Having said that, for me pen and squared paper were what I needed to really understand what any combination of threading, treadling and tie up will do for a drawdown.
Drafts intended for multi shaft looms can be woven on a rigid heddle loom, definitely up to four. True, the structure of a rigid heddle does impose constraints and requires some creativity, but it can be done in various ways. I do find that understanding how a rigid heddle loom can function as a multi shaft loom quite liberating, so some more thoughts on this follow below.
Rigid Heddle Loom as Multishaft loom
As discussed above, a rigid heddle loom setup with a single heddle can be seen as a two shaft loom: the holes are heddle 1, the slots are heddle 2. Now what if you add another rigid heddle? if you do, you will be adding one more shaft.
Hang on, you may ask, did we not just say that a single heddle counts as two shafts? Yes, but that is true for the first heddle only. When you add a second heddle, it is still the case that you will be able to lift the threads that go through the holes of that additional heddle, and we will say that such threads belong to shaft 3. But the threads that go through the slots will still be “passive”, and in order to “lift” them you will have to lower all the other heddles, to lower the hole threads. Hence by adding each furhter heddle, you are only adding one more possibility of manipulating threads through holes.
In short then:
1 rigid heddle = 2 shafts
2 rigid heddles=3 shafts
3 rigid heddles =4 shafts
and so on. I find it more convenient to number the “shafts” starting from the holes, and leaving the slots as (residual) shaft 4.
To learn more about four shaft weaving on the rigid heddle loom, I recommend the excellent Weaving With Three Rigid Heddles, by Reverend David B. Mckinney. The Xenakis Technique for the Construction of Four-Harness Textiles on a Rigid-Heddle, by David Xenakis, has the advantage of being free, thought the writing style may not appeal to all. I found the section on converting four shaft drafts for the rigid heddle loom in chapter 6 Syne Mitchell’s “Inventive weaving on a little loom” pretty clear.