Thread count problems

[David]

I’m having a problem understanding thread counts across the sett. I cant get the numbers to add up. For instance:

A simple sett of R/20 Y16 B10 G/40, according to Croft Weaver tartan design software this has a thread count of 112 which when written out longhand is, R20 Y16 B10 G40 B10 Y16

This to me is not a complete repeat. I would have thought to be a complete repeat; i.e a mirror image about the pivots , the sett would have to include R20 twice; R20 Y16 B10 G40 B10 Y16 R20, which gives a thread count of 132.

What am I not getting?

[Pleater]

I think that there is only one lot of - presumably - red, so one repeat is R20 Y16 B10 G40 B10 Y16 which does add up to 112.

To make it mirror image-able it would have R10 at each end.

Anne the Pleater :ootd:

[figheadair]

Oh dear. This is an example of a non-tartan weaving programme (based on other types of cloth) being offered as a resource for tartan design. This is not a problem confined to software. Years ago I worked with Ann Sutton on her tartan book. She was a professional weaver but had never worked with tartan and so tried, despite advice, to render tartans in standard weaving drafts that are laid out in a table that reflects the threading of the heddles, something completely unnecessary with tartan. The problem is exacerbated by variations amongst software programme that record variously: a half sett with half pivots (the traditional tartan weaver's method), half sett with full pivots (as defined by DC Stewart in his Setts), full count with full pivots and finally full counts with full 1st and 2nd pivots but which omits the 3rd or full repeat pivot. It all depends on how the software was written.

You don’t say whether your starting threadcount has half or full pivots? Assuming the former then the total ends per repeat would be 172 and thus to avoid confusion your count should be written R/20 Y16 B10 G/40 – half pivot counts which all a weaver needs to know to weave the cloth. Computer programmes written by a non-weaver are a bit a curate’s egg.

[The Wizard of BC]

One of the best explanations of thread counts is on the website of The Scottish Tartans Authority.

http://www.tartansauthority.com/tart...thread-counts/

To show where the pivot point is, in a thread count, you usually list the numbers slightly differently. One way is to use a slash(/).

In your example your thread count would look like this;

R/20 Y16 B10 G/40

This is known as a Half Sett. A mirror image of this would be the other half of the full Sett.

Your pivot points would be the left edge of the red band - then across the pattern to the right edge of the green band.

Here is the Full Sett showing the pivots;

R/20 Y16 B10 G/40 B10 Y16 (This is your 112 threads)

[figheadair]

You may also find this article of interest.

[David]

Thanks for the information and guidance. I'm still not 100% certain about the correct way, but for my own purposes (if I ever register and have my own tartan woven) I will go with what I think is the traditional method of notation, half sett with half pivots. This seems to me to give the mirror image that I have seen described on some sites, which also makes more sense to me than stopping one colour short of where you started.

So for my example R/20 Y16 B10 G/40 = 112, to get in my minds eye what the full sett of 112 threads would look like, I will think of the pattern as: R10 Y16 B10 G20 pivot point G20 B10 Y16 R10 = 112 threads. Which I believe when written in the traditional half set half pivot notation would be: R/10 Y16 B10 G/20. Am I correct?