One question that comes up from time to time is how to weave plain weave on a given threading.
Contrary to popular belief, weaving plain weave is NOT simply a matter of lifting first all the even shafts and then all the odd shafts. If a threading alternates odd and even shafts throughout, then even shafts vs. odd shafts does create plain weave. However, many threadings do not alternate odd and even and plain weave is still possible.
The question can be reframed like so: Is it possible to create a shed that lifts every other warp thread and only those threads? To determine whether the answer is yes or no, follow these steps:
- Starting from one end of the threading, circle the first warp end. Skip the next and circle the third, skip the fourth and circle the fifth, and so on. Work across the threading circling every other warp end.
- Make a list of the shafts all the circled ends are on. There’s no need to list a shaft twice; once it’s on the list, it’s on the list.
- Make a second list of all the shafts the not circled ends are on. Again, no need to repeat shafts in the list.
- Compare the lists. If any shaft is on both lists, there is no shed that will create plain weave.
Be careful with repeats! The same warp ends might not be circled on each pass through a repeat. When using this method, it is a good idea to include a few threads from the second repeat.
If no shaft appears on both lists, then plain weave is possible. Tie one treadle to all the shafts on the first list (of circled warp ends) and another treadle to all the shafts on the second list (non-circled warp ends). These are your two tabby treadles.
Why does a shaft appearing on both lists mean plain weave is impossible? Because it means that the threads on that shaft need to be in both the top layer of the shed and the bottom layer of the shed, and there’s no way to make that happen.
Example 1:
Shafts with circled warp ends: 2, 3, 4, 5, 6, 7, 8, 1
Shafts with non-circled warp ends: 1, 2
Shafts 1 and 2 appear on both lists, so there is no plain weave possible on this threading.
Example 2:
Shafts with circled warp ends: 1, 2
Shafts with non-circled warp ends: 3, 4, 5, 6
No shafts appear on both lists, so plain weave is possible. One plain weave treadle is tied to Shafts 1 & 2 and the other is tied to Shafts 3, 4, 5 and 6.
The next time you are looking at a draft, and wondering “what else can I weave with this threading”, you now have a quick way to find out if plain weave is one of your choices!
NOTE: This blog was originally published in the Weavers Toolbox, which is available to Academy members.
