a) Pick Bar
A band, of one of the following types, in which the pick spacing is different from that in the normal fabric:
1. Starting Place
A prominent band in a woven fabric that has one clearly defined edge and that gradually merges into normal fabric, and is caused by an abrupt change in pick spacing followed by gradual reversal to normal pick spacing. Such a bar occurs on restarting the loom without sufficient care after
i) pick finding,
ii) uneven weaving or pulling-back, or
iii) prolonged loom stoppage.
aa) These bars may also be referred to as "standing places" or "pulling-back places" if the precise cause is" unknown.
bb) In knitting, the band has several courses containing stitch lengths longer than in adjacent normal courses and has resulted from a machine stop that has caused changes in warp tension.
2. Weaving Bar
A band that usually shades away to normal fabric at both its edges.
It owes its appearance to a change in pick spacing, and may repeat at regular intervals throughout an appreciable length or even the whole length of the piece, and is the result of some mechanical fault in the loom, e.g. faulty gearing in the take-up motion, bent beam gudgeons, uneven or eccentric beam ruffles, uneven bearing surfaces at some point in the let-off motion, etc. Bars of this type associated with the take-up or let-off motions are also referred to as "motion marks".
b) Shade Bar
A band that has developed a different colour from the adjacent fabric during (or subsequent to) dyeing and finishing, owing to damage to (or contamination of) otherwise normal fabric or weft yarn prior to weaving.
c) Tension Bar
A band composed of weft yarn that has been stretched more (or less) than the normal weft prior to or during weaving.
This abnormal stretch may have been imposed during winding by faulty manipulation or by some mechanical fault in the loom; during weaving by incorrect tensioning in the shuttle; or may have arisen owing to faulty yarn having been excessively moistened at some stage and stretched more than the normal yarn under normal applied tensions. It may appear as a cockled bar in those cases where stretch has been sufficient. (See also cockle (fabric).
d) Weft Bar
A band that is solid in appearance, runs parallel with the picks and contains weft that is different in material, count, filament, twist, lustre, colour or shade from the adjacent normal weft.