Posted by Marla Mallett on July 26, 1999 at 14:08:53:
In Reply to: Re: Weft ease and a Senneh posted by Wendel Swan on July 26, 1999 at 09:32:12:
Dear Wendel and all,
WARP TAKE-UP (actually better than "loom take-up") refers to the small amount of warp that is "lost" (or "taken up" or shortened) when the warps are forced out of their straight paths. How much take-up occurs depends precisely on how the WEFTS are inserted, as I explained before. The amount of warp take-up has little to do with whether the loom is a simple village construction or an elaborate workshop affair.
As for the Senneh piece you've mentioned, it sounds simply like inconsistent (sloppy?) weaving. Poor quality control! Looser warp tension can cause the weave to expand a little...but city workshop looms ought to have BETTER mechanisms (nice ratchets, etc.) for adjusting warp tension precisely and frequently. On a roller-beam type of loom, the tension is readjusted every time the finished portion of the rug is moved downward...between times as well, if necessary. On a continuous, circular warp, such as used in some workshops, if there is any substantial warp take-up the warp would get continually tighter...Thus there would have to be a provision for loosening the tension as the weaving proceeded...On the other hand, wool warp yarns stretch, so sometimes need to be tightened. Humidity changes as well as tension on the wool yarns themselves can make keeping a warp in excellent condition pretty tricky. The widespread switch to cotton warps in Iran was for good reason!
To get back to the Senneh piece...The cause of the weave spreading--the pattern elongating--could thus be EITHER increasingly loose warp tension, or a decrease in the amount of weft ease allowed. It's impossible to say which without seeing the piece. People tend to assume that such problems have to do with how much beating is done, but this is not usually the crucial factor.
I don't know if this is clear??? If not, I'll try again.
Marla