There are lots of different treadling systems you can use on an overshot threading to produce fabric at least a little and often VERY different in structure, texture, and appearance from regular overshot. There’s shadow fashion, echo, Italian fashion, flamepoint, honeycomb, swivel, petit point… Each one is beautiful and useful in its own way.

When I teach a class on treadling variations for overshot threadings, though, the variation I always start with is one called double tabby, and it looks almost exactly like regular overshot! In fact, if you don’t know what to look for, you’d be hard pressed to tell there’s any difference.

Can you tell which of these three bands is regular overshot and which is double tabby?

If it looks almost the same, what’s the advantage? Why bother learning and doing something new if you can’t even tell that it’s different? Because it’s faster!

Weaving regular overshot

Overshot has two wefts: a pattern weft and a tabby weft. In regular overshot, the pattern weft is usually about twice as thick as the warp, and is thrown through the 2/2 twill sheds in whatever order is required to create the desired pattern. The tabby weft is usually the same weight as the warp or a little finer, and is thrown through alternating plain weave sheds.

In other words, the weaving goes like this:

1. The heavy pattern weft goes through some 2/2 twill shed
2. The fine tabby weft goes though one of the plain weave sheds
3. The heavy pattern weft goes through some 2/2 twill shed
4. The fine tabby weft goes through the other plain weave shed

Over and over and over, for the length of the project. Here’s the draft for the above fabric when woven as regular overshot: 

Notice that, since every pattern pick is followed by a tabby pick, there are the same number of each.

Weaving overshot with double tabby

In double tabby, one of the pattern picks is left out of this sequence of four picks, like so:

1. The heavy pattern weft goes through some 2/2 twill shed
2. The fine tabby weft goes through one of the plain weave sheds
3. The heavy pattern weft goes through some 2/2 twill shed
4. The fine tabby weft goes through the other plain weave shed

Without that second pattern pick, the two tabby picks are right next to each other, hence “double tabby.” 

Here’s what that looks like in a draft and drawdown:

Notice that there are now half as many pattern picks as tabby picks, so the pattern weft needs to be doubled in order for the design to square up like normal.

Why it’s faster

There are several reasons why double tabby is faster than regular overshot. 

The most obvious is that there are 25% fewer weft picks overall, and only half as many pattern picks. Since the pattern picks are the ones you need to pay attention to, eliminating half of them speeds things up a lot.

There’s the usual number of tabby picks, it’s true, but they’re faster to weave than normal because they come together. That’s got two big advantages: it’s easier to keep track of, and it requires changing shuttles half as much. 

Suppose you start with the tabby shuttle on the left side of the warp. When it’s time to weave the tabby, you throw the first tabby pick from left to right, beat, change the shed, and throw the tabby shuttle back to the left again. The tabby shuttle always starts and ends on the same side of the warp.

That’s easier to keep track of than “left tabby treadle if the shuttle is on the left and right tabby treadle if the shuttle is on the right.” That rule still applies, but you’ll always start with the same treadle (the left, in our example) every time you pick up the tabby shuttle. 

In regular overshot, you need to switch shuttles after every single pick, or four times per treadling sequence. In double tabby, you only need to switch shuttles twice per sequence: once from pattern to tabby, and once from tabby to pattern after both tabby picks have been woven. 

Methods of doubling

You’ve got a few options for how to double the pattern weft:

1. Double the regular pattern weft on the bobbin, or
2. Use a pattern weft that’s four times as heavy as the warp rather than just twice as heavy, or
3. Throw the regular pattern weft through the shed twice.

Option 1 is the usual choice, at least in the historical double tabby coverlets found in The Coverlet Book (Bress, 2003). It requires a bit of care when winding the bobbin so that the two strands wind on and then off again at the same rate. That’s not hard with some practice.

Option 2 is just as fast as Option 1 and doesn’t require doubling the yarn. It’s a good choice if you happen to have a pattern weft of the right weight. If you want to use the same pattern weft as usual, though, you need to choose Option 1 or 3.

Option 3 seems like it would slow things back down to the speed of regular overshot, since it means throwing the shuttle four times per sequence. It doesn’t entirely, though, since you still don’t have to switch shuttles between the two passes of pattern weft through the same shed or between the two tabby picks. 

This option also means you can start the pattern weft from one side and the tabby weft from the other, and they’ll always return to their own side every single time you pick up the shuttles.

The same but different

Now that you know a little more about it, can you tell which of these bands is woven in double tabby and which in regular overshot?

The bottom band is regular overshot. The top two bands are woven in double tabby, one with Option 1 and one with Option 3. The way to tell them apart is by looking at the halftones. In the bottom band, the halftone pinstripes are stacks of six very small little dots. In the top two bands, the pinstripes are stacks of three slightly bigger dots.

As you can see, the difference between the bottom band and the other two is pretty subtle – there’s certainly nothing in the top two that detracts from the design. There’s nothing at all to tell one method of doubling the pattern weft apart from the other, so they’re equally good choices, too.

Not just for wool

Here’s another sample, this time woven with a cotton pattern weft that doesn’t bloom as much as wool:

Look at the halftones – you should be able to tell which band is double tabby and which is regular overshot.

Keep in mind that both these samples and the purple ones above were woven on a ground of 8/2 cotton sett at 16 EPI. If you work in finer threads, the difference in the halftones will be even less pronounced. 

Next time you’re weaving overshot, consider weaving at least a sample of double tabby to see how it feels, what it looks like, and whether you find it faster or more awkward. It never hurts to add one more option to your repertoire, especially if it makes things easier and speeds things up!

---

From the course Color Mixing 1