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You receive a shipment of "140cm" width silk. You unroll it, lay it flat, and measure. It reads 136cm. You measure again – 136.5cm. The supplier's spec sheet says 140cm ±2%. That should be fine, right?

Measuring silk fabric width – nominal vs effective width

Not quite. Because when you cut into that roll, you discover that the effective usable width – after removing selvedges, dealing with bowing, and accounting for the narrowest sections – is often 3–8cm less than what you expected. And that small difference can add 5–10% to your fabric consumption per garment.

This is one of the most overlooked cost drivers in silk sourcing. You negotiate the price per metre carefully, but if the width is short, you're effectively paying more per usable square metre – and your cutting yield drops.

Let's break down exactly what's going on, why it happens, and how to protect yourself.

Nominal vs Actual vs Effective Width – Three Different Numbers

Nominal width is the width stated on the mill's spec sheet – typically 140cm, 114cm, 55 inches, or 44 inches. This is the target the loom is set to.

Actual width is what you measure when you unroll the fabric and lay it flat without tension. It can be higher or lower than nominal, but in practice it's often slightly below nominal due to finishing shrinkage.

Effective width is the true usable width – the width you can actually cut into. It excludes:

  • Selvedges – the tightly woven edges, usually 1–2cm per side, which are often too dense or stiff for garment panels.
  • Bowing and skewing – when weft yarns are not perpendicular to the warp, the pattern shifts and reduces usable area.
  • Narrow spots – tension variations during weaving can create sections where the fabric is 2–3cm narrower than the roll average.
Real-World Example

A roll with nominal 140cm width, after selvedge removal (2cm each side) and allowing for 2cm of bowing or width variation, often has an effective width of only 132–135cm. That's a 4–6% loss in usable area – which directly increases your fabric cost per garment by the same percentage.

Why Does Silk Width Vary?

Silk fabric is more prone to width variation than many other textiles for several reasons:

  • Warp tension inconsistency – During weaving, if the warp yarns are not held at uniform tension, the fabric width can fluctuate. This is more common in lightweight silks (e.g., 8mm chiffon) than in heavier weaves.
  • Finishing shrinkage – Silk fibres relax and contract during degumming and dyeing. The hotter the water and the longer the process, the more the fabric narrows. Some mills compensate by weaving wider, others don't.
  • Humidity – Silk is hygroscopic. In high humidity, it can expand slightly; in dry conditions, it contracts. Width measured in a humid warehouse may differ from width measured in an air-conditioned cutting room.
  • Loom type and speed – Older shuttle looms often produce more width variation than modern air-jet or rapier looms, especially when running at high speed.

The Financial Impact – A Simple Calculation

Let's say you're ordering 100 metres of 25mm charmeuse at $12/m, nominal width 140cm. You plan to cut a dress that requires 2.5 metres of fabric at 140cm width.

If the effective width is only 134cm, you now need 2.61 metres per dress – an extra 4.4%. Over 100 metres, you lose 4.4 metres of usable fabric – that's 1.76 fewer dresses than you planned, costing you about $53 in lost output, not counting the impact on your production schedule.

Now scale that to 500 metres or 1000 metres. The cost adds up quickly.

How to Protect Your Cost – A Checklist

Before ordering:

  • Ask the supplier: "What is your typical effective width after selvedge removal?" Don't accept nominal width as the answer.
  • Request a width tolerance in writing – e.g., "actual width must be at least 135cm at all points."
  • Order a pre-production sample (a few metres) and measure it yourself under controlled conditions.

Upon receipt:

  • Measure width at three points – start, middle, end – and average them. Record the minimum.
  • Subtract selvedge width (usually 1–2cm each side) to get effective width.
  • If the effective width falls below your agreed minimum, take photos, document, and raise it with the supplier immediately.

In your cutting room:

  • Adjust your marker layout to the minimum effective width recorded – don't assume the average.
  • For large orders, consider splitting the roll into width-matched batches to optimise cutting.

What Silk.Sale Does Differently

When I inspect silk in Nanchong, I don't just check colour and weight – I measure width at multiple points along the roll. If the width is consistently below the agreed effective minimum, I flag it and work with the mill to either correct it, discount it, or replace it.

You shouldn't have to discover this problem after the fabric is already on your cutting table. That's why I send video evidence of width measurements with every shipment – so you know exactly what you're getting, down to the centimetre.

Frequently Asked Questions

Nominal width is the width stated on the mill's spec sheet – typically 140cm, 114cm, or 55 inches. Actual width is what you measure when you unroll and lay the fabric flat. Effective width is the true usable width after deducting selvedges, shrinkage, and any irregularities. In many cases, the effective width can be 3–8cm less than the nominal width, which directly affects how many garments you can cut from each meter.
Several factors contribute: tension inconsistency during weaving (warp tension variations cause narrow spots); finishing shrinkage (relaxation and drying can pull width); selvedge waste (selvedges are often unusable and must be trimmed); and humidity conditions (silk fibres absorb moisture and can change dimensions). Mills typically allow a tolerance of ±2–3% on width, but in practice the variation can be larger, especially for lightweight or loosely woven silks.
Lay the fabric flat on a smooth, hard surface without stretching it. Use a metal tape measure and take measurements at three different points – near the start, middle, and end of the roll – and average them. Exclude the selvedge edges (usually 1–2cm on each side) to get the effective usable width. Record the minimum measurement, because that is the limiting factor for your cutting layout. Compare your results against the supplier's declared width and agreed tolerance.
Before placing an order, specify your required minimum effective width (e.g., "usable width must be at least 135cm after selvedge removal"). Ask the supplier to confirm their typical width range and tolerance. Request a pre-production sample to measure yourself. If the width consistently falls below your minimum, negotiate a price adjustment or a replacement. A good supplier will be transparent about their width control – if they are evasive, consider it a red flag.

I find. I check. I seal. You relax.