Quote Originally Posted by M. A. C. Newsome View Post
In looking at this specimen under a high zoom, I notice that there are two threads of blue between the green and red. Do you know if this feature is consistent throughout, Peter, or is that one of the mysteries we'll have to wait for the larger piece to solve?
Well spotted Matt. I'd missed that.

Here's an extract at a higher-res to show the detail (turned through 90o to fit the page). You'll see that there is only one blue thread, the second one in, and that in fact the colouration is inconsistent and that at some points it's green.



I've no doubt that what we have here is an example of faulty dyeing. Green was normally, probably always, made by dyeing yarn blue and then top dyeing with a yellow. An area where any dye doesn't take fully is the result of one of several causes including: the skein being tied too tightly; being unevenly mordanted; a section being dry or contaminated in some way.

I expect that this faulty dyed thread would run across the width of the cloth for some way, maybe the whole width, maybe part-way, maybe back again for some distance. I guarantee that it won't appear in the same place throughout the piece but such poor dyeing is likely to appear elsewhere in the cloth as and when that dyed section of the skein appears. It's likely that it will appear in both warp and weft.

Such dyeing faults are not uncommon in C18th specimens and even today amongst natural dyers and result from dyeing, generally large quantities of yarn, with poor equipment in bad conditions.

Finally, the other thing that such a fault confirms is that the dyeing was done as it is today, after the yarn was spun as opposed to dyeing 'in-the-fleece' which is the practice for tweed.