Specification guide · 5 min read
How to read a fabric specification
By Dinesh Chhabra, CEO, Vidhi Fabrics · Published
A fabric specification is a shortlisting tool, not proof a cloth is right. Composition states fibre content, not behaviour; construction — yarn count, sett and weave — decides drape, opacity and handle far more. Ask for shrinkage, fastness and handle separately, then let an approved physical sample make the final call.
A specification is a shortlisting tool. It lets you compare candidates without holding them, ask precise questions, and hold a supply to account afterwards. What it cannot do is tell you whether a cloth is right, because the fields that decide how a fabric behaves are not the fields most buyers read first. This guide goes through a spec sheet in the order that matters: what each line is really saying, which lines separate two cloths that look identical on paper, and what the sheet never carries at all.
Composition tells you less than the percentage suggests
A blend ratio is a statement about fibre content, not about behaviour. Two cloths both written as 55 per cent cotton and 45 per cent linen can differ in which fibre is in the warp and which in the weft, whether the blend is intimate or plied, and what the linen actually is. Each of those changes shrinkage, dye uptake and handle more than the ratio does.
Ask where the blend happens. A yarn spun from mixed fibre behaves differently from a cloth woven with one fibre one way and another fibre the other, even at an identical stated ratio. The spec sheet rarely says which, and the difference shows up in the first wash.
Treat descriptive names with more caution than percentages. Terms that describe an effect rather than a content — a linen look, a silk finish — are not composition claims and should not be read as though they were.
Construction is where two identical weights stop being identical
Yarn count, ends and picks, and weave are the three fields that explain most differences a buyer notices and cannot name. Count is the fineness of the yarn; ends and picks are how many threads run each way per inch; weave is how they cross. Together they decide drape, opacity, strength and how the surface takes light.
This is also the answer to why what the cloth weighs is not enough on its own. A coarse yarn loosely set and a fine yarn densely set can land on the same weight and behave nothing alike, and the construction fields are where that shows up on paper before it shows up in your hands.
If a specification gives weight and composition but no construction, it is not describing a cloth so much as a category. Ask for count and sett before treating it as a candidate.
As an illustration: a 40s cotton count set densely, at over 100 threads per inch each way, behaves differently from the same 40s count set loosely, at around 60 threads per inch. The weight of the two can land close together; only the count-and-sett line on the specification tells them apart.
Finish changes the cloth, and not all of it lasts
A finish is applied after weaving and it can move nearly every property on the sheet, including weight and the width you can actually cut. Mercerising, calendering, sanforising, easy-care resins and coatings each change something, and a figure quoted before finishing is not the figure that arrives.
Ask how permanent a finish is, because the answer differs sharply. A mechanical finish set into the fibre behaves differently over a garment life from a surface treatment that washes out over some number of cycles. A cloth chosen for a handle that disappears after five washes was chosen on a property it did not really have.
Where a finish carries a performance claim, ask what standard it was tested to and whether a report exists. An untested claim on a spec sheet is a description, not a specification.
What the sheet leaves out
Shrinkage, colourfastness and handle are the three that matter most and appear least. None of them can be inferred from weight, composition or construction with any confidence, and all three decide whether a buyer accepts the finished goods.
Ask for them separately and in writing. Residual shrinkage after washing — tested to ISO 6330 — fastness to washing, rubbing and light, and a physical sample for handle. These are ordinary requests and a supplier who cannot answer them is telling you something useful.
Then let the sample decide. The specification is how you get from many candidates to a few and how you hold a lot to account once it ships; the cloth in your hand is the only thing that tells you it is right.
Fields to require on any quotation
A specification carrying all of these can be compared. One missing half of them cannot.
- Composition, with where the blend happens — yarn or weave
- Yarn count, and ends and picks per inch
- Weave, named rather than described
- Weight, stated as greige or finished, with a tolerance
- Cuttable width, stated as greige or finished, with a tolerance
- Finish, with how permanent it is and any standard it was tested to
- Residual shrinkage and fastness figures, asked for separately
Frequently asked questions
- Which fields should I insist on before asking for a sample?
- Composition, weight with its tolerance, cuttable width with its tolerance, and construction — count, sett and weave. Those four let you rule out most candidates on paper, which is the whole purpose of a specification. Everything else is better settled against the sample.
- Two suppliers describe the same cloth differently. Which one is right?
- Often both, describing different stages or different fields. One may be quoting greige where the other quotes finished, or naming a weave where the other names an effect. Put the two sheets side by side field for field and the disagreement usually turns out to be a gap rather than a contradiction.
- The composition says one thing but the cloth handles like another. Is the sheet wrong?
- Usually not. Handle comes from construction and finish far more than from fibre content, so a stated composition can be accurate while the cloth feels nothing like what you expected. Check count, sett and finish before questioning the composition — that is where the explanation almost always sits.
