Warp and Weft
The two thread systems in a woven fabric: the warp runs lengthwise under tension, the weft runs across it, interlaced by the weave.
Weaverine weaves on 650+ waterjet looms at 160–330 cm, and the warp-and-weft distinction is what decides sett, selvedge and which direction a cloth can be railroaded.
By Wren Thunderborn, Head of Content
Every woven fabric is made from two perpendicular thread systems, and almost every weaving term in trade is a statement about one of them.
- Warp — the threads running lengthwise, held under tension on the loom beam.
- Weft (also filling, or pick) — the thread carried across by the shuttle or rapier, interlacing with the warp.
In counting terms the warp threads are ends and the weft threads are picks:
| Yarn | Counted as | Abbrev. | Runs | Tension |
|---|---|---|---|---|
| Warp | ends | E | lengthwise | High and constant |
| Weft | picks / picks per inch | PPI / ends per pick | across | Low, intermittent |
So ends per inch (EPI) describes the warp and picks per inch (PPI) the weft. Together they give thread count — see thread count — but the split matters, because the two thread systems do different jobs.
Warp and weft interlacing (schematic)
The vertical system is the warp, held under tension. The horizontal system is the weft, carried pick by pick. Which one you see on the face is a construction choice.
Dark = warp on the face. Light = weft on the face.
What each system actually does
| Aspect | Warp | Weft |
|---|---|---|
| Job in the cloth | the skeleton: holds the fabric, carries the load | the fill: coverage, body, the surface you touch |
| Yarn | stronger, lower elongation | usually softer, more prone to abrasion on the face |
| On the loom | mounted under tension before weaving starts | carried and interlaced, then beaten into place |
| If it goes wrong | breaks run lengthwise; tension bands run down the roll | picks run across; a missing pick shows as a weft bar |
| After the loom | already stretched, so most shrinkage shows across | takes up the shrinkage |
That last row is the one buyers hit: a fabric that measures wider on the loom than on the table is a warp-side fact, and the shrinkage allowance on the PO is what reconciles it.
Why the warp carries the tension
The warp is the structural skeleton. It is mounted under tension before weaving starts and stays under tension for the whole fabric, which is why it typically uses a stronger, lower-elongation yarn than the weft.
This is the single fact behind a lot of practical behaviour:
| Property | Consequence |
|---|---|
| Warp tension | Set at the beam; too little and the cloth is unstable, too much and the yarn is stretched and will relax later |
| Width | Determined by the number of ends × reed spacing — the width is a loom setting, not a property of the yarn |
| Weft | Carried and interlaced, then beaten into place; the take-up and let-off keep it at a stable angle |
| Shrinkage | The warp is already stretched, so most shrinkage shows as a change in the weft direction |
| Defects | Warp breaks and uneven tension run the length of the roll; weft faults run across it |
The practical consequence: a fabric defect that runs with the length is a warp-side problem, and one that runs across is a weft-side problem. On an inspection table that single distinction tells you where to look.
Which system is on the face
The face of a fabric is whichever system the weave leaves on top, and the choice is written into the construction rather than into the fibre:
- A weft-faced cloth shows the weft across the width — a 1/1 plain weave is the usual example.
- A warp-faced cloth shows the warp lengthwise — the face that takes the rubbing, and the one whose yarn has to survive it.
- A double-faced cloth puts one system on each side, and then the two faces can behave differently under wear.
This is why "which side is the face" belongs on a PO whenever the construction is not plain: the same roll can wear differently depending on which way the panels are cut.
Ends and picks on a wide loom
This is where a mill becomes worth talking to directly. Fabric width is set by how many ends the reed spaces across the working width, so a wider cloth is not a wider version of a narrow one — it is a different reed, a different end count, and a different tension profile across the span.
| Weave | What it changes | What stays constant |
|---|---|---|
| Warp count up | Finer, denser, more stable in the length | The weave type and the yarn |
| Weft count up | Fuller hand, better coverage across | The warp tension |
| Both up | Higher weight, more body | The finishing route needed |
On a waterjet loom both systems are carried by water rather than by air, which is what allows the full width to be held consistently — and why a wide waterjet cloth is normally the practical way to get a stable wide construction.
What to put on the purchase order
- The construction, in trade notation: 1/1 plain, 2/1 twill, 3/1 twill, and the ratio is not optional
- Ends per inch and picks per inch — the two counts, not the total
- Which side is the face, and the direction of the wale if the look depends on it
- Fibre, width in cm, GSM, and the finish, on the same line
- How the width is measured: on the loom, or on a relaxed sample — and the tolerance either way
- A sealed swatch when the construction or the face is part of the brand look
Mill greige context
Weaving is where Weaverine's own capability is most specific. On Weaverine greige polyester programs the woven base sits roughly in the 55–120 GSM range at 160–330 cm widths, produced on 650+ waterjet looms with dual-jet insertion, and a dobby head on the existing waterjet for small woven figures and combination weaves such as satin stripe.
That last point is the one worth understanding: the dobby is an attachment on the waterjet, not a separate jacquard hall. It is what lets a small figure or a band be woven on the same machine as the plain and twill base — which is why a figured weave here is a specification question rather than a different mill.
Weaverine does not publish ends-and-picks figures on this page. They follow the construction, the yarn and the loom setting, and a generic number would describe a cloth nobody ordered. Send the ends/picks with your GSM and width and ask whether it is achievable on your construction.
For the simplest interlacing of the two systems, see plain weave, and for the diagonal that a twill makes out of them, see twill weave.
Common questions
What are warp and weft?
- They are the two perpendicular thread systems every woven fabric is built from. The warp runs lengthwise on the loom beam, held under tension for the whole cloth. The weft runs across, carried pick by pick and interlaced with the warp. Every weaving term in trade is a statement about one of them.
Which way does the grain run?
- Along the warp. The grain line of a fabric runs parallel to the warp threads, which is why a cut that goes off-grain shows up as a diagonal distortion in the finished panel. The weft direction is called the cross-grain, and it is where most of a fabric's stretch sits.
Why does the warp need more tension than the weft?
- Because the warp is under tension for the whole fabric while the weft is only intermittently loaded. Too little and the cloth is unstable on the loom; too much and the yarn is stretched, so it relaxes later and the width changes after the loom. That is why a width quoted at the loom and a width measured on a relaxed sample are not the same number.
Are ends and picks the same as thread count?
- No. Thread count is the total of both systems in a square inch; ends per inch (EPI) is the warp alone and picks per inch (PPI) is the weft alone. The split decides how the cloth behaves, which is why a PO that names only thread count has not said enough.
What does a warp-faced fabric mean?
- That the warp sits on the face and the weft is hidden behind it, as in a warp-faced twill or warp satin. It is the opposite of a weft-faced construction, and it changes the abrasion behaviour, the drape and how the cloth wears: the face takes the rubbing, so the yarn on the face is the yarn that has to survive it.
How do you specify ends and picks on a purchase order?
- Name the construction (2/1 twill, 1/1 plain), the ends per inch and picks per inch, the fibre, the width, the GSM and the finish on one line, and say which side is the face. A construction without the two counts leaves the cloth defined only by a photograph.
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