In a correctly finished fabric, the weft yarns (in wovens) or courses (in knits) run straight across the width at right angles to the selvedge. Bowing and skewing are distortions of this line. They are sometimes called "weft distortion" or "filling distortion".
Definitions#
- Bow: the weft line curves, like a smile or a frown across the width. The center lags behind or runs ahead of the edges.
- Skew: the weft line is straight but runs at an angle across the width; one selvedge is ahead of the other.
- Double bow or hooked distortions are variations where the curve is uneven.
Measuring#
Lay the fabric flat without tension. Draw or follow a weft yarn (or a course, or a stripe) across the width. Draw a straight reference line at right angles to the selvedge from the point where the weft meets one edge.
Bow#
Measure the largest distance between the weft line and a straight line joining the two points where the weft meets the selvedges.
Skew#
Measure the distance along the selvedge between the reference line and where the weft reaches the other edge.
Test methods such as ASTM D3882 describe the procedure. Use the buyer's method and limits.
Worked example#
A fabric is 150 cm wide.
- The weft line bows 2.1 cm from the straight line at the center: bow = 2.1 / 150 × 100 = 1.4%
- On another roll, the weft reaches the far selvedge 3.0 cm ahead of the reference line: skew = 3.0 / 150 × 100 = 2.0%
Causes#
| Cause | Effect |
|---|---|
| Uneven tension across the width during finishing | Bow: center pulled more or less than edges |
| Stenter clips or pins feeding one side ahead of the other | Skew |
| Weft straightener not set or not working | Bow and skew not corrected |
| Uneven rolls or batching | Distortion set in by heat |
| Fabric twist in knits | Course skew, related to spirality |
Why it matters#
- Stripes and checks will not match across seams or will look slanted.
- Garments twist after washing when panels are cut on a distorted grain and the fabric relaxes.
- Panels are off-grain, so the garment hangs unevenly.
Control#
- Weft straighteners on the stenter, with sensors that detect the weft angle and correct it.
- Even tension and good roll handling through finishing.
- Check every lot at fabric inspection, and record bow and skew with the 4-point inspection results.
- Cut on grain: for distorted fabrics, align patterns to the weft or stripe, not to the fabric edge, if the buyer accepts the fabric.
Knitted fabrics#
In knits, course skew is linked to spirality. Straightening at the stenter can pull courses straight, but if the yarn torque remains, the fabric can twist again in washing.
See the bowing and skewing defect guides for troubleshooting.
Related guides#
- Fabric defects: where bow and skew sit among the other fabric faults found at inspection.
- Fabric shrinkage: why skewed fabric often shrinks and twists at the same time after washing.
- Fabric spreading: how to lay striped and checked fabric so distorted rolls do not reach the cutting table unnoticed.
- Fabric testing standards and methods: the full range of fabric tests, including skewness after washing.
Frequently asked questions#
Is bow or skew worse for garments? It depends on the product. Skew is usually more damaging for plain garments because it makes panels hang off-grain and can make side seams twist after washing. Bow is more visible on stripes, checks and printed repeats, where a curved line across the chest or back is easy to see.
Can a distorted fabric be corrected at the garment factory? Not reliably. Straightening needs heat, moisture and controlled tension in a finishing range. A garment factory can only reduce the effect by cutting panels on the true grain, which costs extra fabric and time.
Why does a fabric pass bow and skew at the mill and fail at the factory? Rolls can relax during storage and transport, and measurement methods can differ. Agree the method and the measuring point (roll start, middle, end) with the supplier.
Should I measure on every roll? Measure on the rolls sampled for 4-point inspection, at the start and end of each roll, and on every roll of striped or checked fabric where pattern matching matters.