Composition is the figure that gets written into a purchase order and then measured by nobody. This is what it controls, how to measure it, and what happens when it drifts.
What composition actually controls in cotton/T.C
Shrinkage, hand, price and the care label all follow from this.
It also explains why composition is the first line a buyer loosens and the last line a claim refers to.
For Cotton and T/C fabric, the working range is 100 % cotton / 65-35 / 80-20 T/C. Inside that band the choice is commercial; outside it, the product changes category and so does the price.
How to choose a composition option
| Option | What it changes in cotton/T.C | When it is the right choice |
|---|---|---|
| 100 % cotton | The lowest-cost option in the family. Shrinkage is where it usually ends up. | Cost-led programmes with a short service life |
| 65-35 | The volume middle: enough margin for process variation without paying for headroom the end product cannot use. | Most repeat programmes, and the safest default |
| 80-20 T/C | The top of the family, where the process is controlled tightly enough to guarantee it. | A warranty, a tender, or a specification that cannot be renegotiated |
These are alternatives, not points on a scale. Composition is chosen by the application rather than by price, and a supplier who quotes one option as if it were interchangeable with another is quoting a different product.
Buyers default to the floor because it is the cheapest compliant answer. That is rational until the first claim, and then the saving is measured against a replacement shipment.
The figure that decides the outcome is not composition itself but the tolerance around it. A supplier who quotes 100 % cotton / 65-35 / 80-20 T/C without a tolerance has not quoted a specification, and the first lot will define the tolerance for you.
How to measure composition
The reference method here is Shrinkage, run to ISO 6330 + ISO 5077, with an acceptance of <= 3 % after 3 washes (pre-shrunk). The method is the easy part; sampling and conditioning are where reports diverge.
Measure on the goods as delivered, not on the greige or the pre-finished material. The figure that matters is the one in the product your customer receives.
Record the measured value rather than pass or fail. A marginal pass on composition tells you the process is running at the edge, which is the information you need before the next lot rather than after it.
Composition does not stand alone
Composition moves with yarn count (16s / 20s / 21s / 32s / 40s) and with construction (1/1 plain / 2/1 twill / ripstop). Tightening one usually costs money in another, and a supplier who accepts every tolerance without comment has either not understood the interaction or is planning to substitute.
If a quotation is significantly cheaper, the difference is usually in one of these neighbours rather than in the figure being discussed.
The clause to write for composition
The line below is the version we can quote against without inventing anything. Composition appears with a tolerance and a test, not as a standalone number.
65/35 polyester/cotton twill, 21s x 21s, 108×58, 240 gsm, 160 cm, sanforised shrinkage <= 3 % after 3 industrial washes, colour fastness to washing >= grade 4, Pantone 19-4127 TCX
The clause that protects you is not the value, it is the sentence that says what happens when the value is missed. Put it in the purchase order, not only in the enquiry.
When composition goes wrong
Shrinkage. Uniforms shrink a size after the first industrial wash.
The cause is usually no sanforising, or sanforising settings not held between lots.
The test that catches it: ISO 6330 at 60 C industrial cycle, 3 washes, then ISO 5077.
What to specify instead: Specify pre-shrunk with 3-cycle figures and require the sanforiser setting in the technical file.
The pattern is consistent: the failure appears months after delivery, is hard to attribute, and the cost lands on the buyer. That is the argument for measuring composition on every lot rather than on the development sample.
Four questions about composition, before you order
- What tolerance do you hold on composition, and what did your last three lots measure against it?
- Which method do you use for shrinkage, and which laboratory signs the report?
- When composition falls outside 100 % cotton / 65-35 / 80-20 T/C, do you rework, downgrade, or ship and hope?
- Which of yarn count or construction would you move first to hit a lower price?
The answers are more useful than a certificate, because they show whether the process is controlled or merely inspected. Full ranges for cotton/T.C are on the product page, and the measurement regime is described on the quality control page.
Questions buyers ask before ordering
Do you supply 3-cycle shrinkage figures?
Yes, and we recommend insisting on them. A 1-cycle figure hides progressive shrinkage, which is what ruins uniforms.
Can you match a shade in both 100 % cotton and T/C?
We can, but the reflectance curves differ and metamerism is real. Approve the swatch under both D65 and TL84.
Seven lines that turn a quotation into a specification
Most post-delivery arguments are not about quality. They are about a document that never said which figure would be measured, on which instrument, at whose cost.
- Shrinkage: <= 3 % pre-shrunk, <= 6 % raw is not an answer on its own. Ask for the last three lots' actual readings and the spread behind them.
- Colour fastness to washing: agree the test method with the number. Two labs, two methods, two answers, one argument.
- Finish (mercerised / sanforised / easy-care / FR): state where in the band this order sits. The middle of the band is not what a tolerance is for.
- Composition: the figure you will accept inside the 100 % cotton / 65-35 / 80-20 T/C band, the tolerance on it, and the method used to measure it.
- Deviation rule: anything outside the agreed bands is reported before shipment, not after arrival.
- Packing and marking: shipping mark, roll or carton count and the tolerance on quantity, since a short shipment is a claim too.
- Who inspects: third-party, in-house or none, decided in advance, with the AQL level written down.
Three questions, and the answers that separate mills
If the cotton/T.C figures on this page is going to be decided on a call, take these three questions into it.
| Question | Answer that should worry you | Answer that holds up |
|---|---|---|
| Which test catches tear at seam? | “We have never had a complaint.” | Formaldehyde — on the production lot, with the acceptance figure written into the report and not into the email. |
| May I see a report for a lot you shipped last month? | “That is confidential customer information.” | A redacted report, which carries every number that matters and none of the customer’s identity. |
| Where in the >= grade 4 band will this order sit? | “In the middle, normally.” | A stated target and the readings behind it. Colour fastness to washing drifting inside the band is how a conforming lot still fails. |
Need composition specified and tested against your end use?
Send the end use, the quantity and the destination market, and we will come back with a specification that meets it, a price at your volume and the test reports that back it up. Samples are free for qualified programmes; we charge the courier only.
Related reading
- Construction in Cotton and T/C fabric
- How to Test Cotton/T.C Before You Commit to a Container
- Workwear and uniforms
Sample cut with your values on it · Neutral packing and private label · Consolidation, documents and lead times
