How to Read a Fabric Spec Sheet

The seven fields on a spec sheet

Composition: the blend decides behaviour

Composition is the first line to read because it governs everything else. A poly-viscose 65/35 blend behaves very differently from pure cotton: more wrinkle resistance, better wash fastness, lower cost, slightly less breathability. Every Benny Cotts suiting states its blend, so you know what you are comparing.

GSM and width: the numbers that cost money

GSM is weight, covered in depth in our GSM guide. Width is the quiet one buyers forget: at 150 cm you fit more garment pieces across the cloth than at 110 cm, so fabric needed per uniform, and therefore cost, changes with width. Always compare fabrics at the same width, and read the width off the specific spec sheet rather than assuming a house standard. Most of our qualities are 147 cm (58 inch), several suitings are 150 cm, and narrower shirting and lining cloths run 142, 91 or 89 cm. On shirting the choice between the two common formats is a cutting-room decision, covered in 36 inch vs 58 inch shirting.

Weave and finish: how it wears

Weave is the construction. Plain is simple and even; twill (the diagonal line in trousers and structured suiting) is stronger and drapes well; dobby adds a subtle woven texture. Finish is the treatment layer: wash-fast holds colour through laundering, wrinkle-resistant reduces ironing, and abrasion-resistant survives high-wear points.

Read weave and finish together with GSM: a 220 GSM twill with a wash-fast finish tells you far more than the weight alone.

Testing and certification: how a claim gets verified

A finish label such as "wash-fast" or "wrinkle-resistant" is a claim; testing is how that claim is checked. Colour fastness is tested separately against washing, light and rubbing, each on its own numbered scale, and shrinkage is tested by measuring a swatch before and after a standard wash cycle. Ask a mill what tests it runs in-house and against what standard, rather than accepting the finish name alone.

This is also where mill-versus-trader matters. A mill that wove the cloth knows the yarn, the loom and the lot behind it, holds the processing records for that lot, and can put a specific batch against a named method and a filed reference standard. A trader reselling finished cloth is repeating whatever the original mill claimed, usually without the lot number that would let anyone check it. Dyeing, finishing and testing often sit with a partnered processing house rather than under the mill's own roof, as they do for us: our weaving is in-house at Village Atoon and our processing runs through partnered houses in Bhilwara. What matters is not whose roof the machine sits under, it is whether the mill can name the lot and produce the report for it.

Strength and abrasion: the methods behind the numbers

Colour fastness reaches a spec sheet already numbered, because everyone quotes an ISO 105 method and a grey scale grade. The physical properties usually do not. A specification will say the cloth must be rated to twenty thousand cycles, or to a number of double rubs, or simply that it needs good tear strength, and none of those means anything until the method sits next to it. Several of our guides tell a buyer to ask which abrasion method and cycle count a fabric is rated to. This is how to read the answer.

Two abrasion families dominate and they are not convertible. Martindale rubs a mounted specimen against an abradant along a figure-of-eight path under a defined load, and reports cycles to a stated end point. Wyzenbeek draws the specimen across an abradant on an oscillating cylinder, and reports double rubs. No reliable conversion factor exists between them, so a specification quoting both numbers for the same cloth is quoting two different tests, and a submission tested on one method cannot be evaluated against a limit written for the other.

The second thing to check is where a large number came from. Cycle counts in the tens of thousands belong to the furnishing world, where a seat cover takes the same rub in the same place for years. The apparel and uniform methods run to a much lower end point, because a garment gives way at a cuff, an elbow or a seam long before a seat cover wears through. A uniform specification that has copied an upholstery figure will read as unmeetable to every mill bidding on it, and the useful conversation is about which method and end point the programme actually needs.

Ask which laboratory ran the test and against which method, and check that the laboratory is one your tender or your export customer accepts, because a report from outside that list can be rejected on procedure alone. Our weaving is in-house at Village Atoon and our dyeing, finishing and testing run through partnered processing houses in Bhilwara rather than an accredited laboratory of our own, so where a programme needs a physical-strength number on record we will say plainly which independent laboratory it should come from. How we test our fabric sets out what gets checked at each stage, and pilling covers the grade side in full.

Breathability: what a spec sheet can actually prove

Breathability is the most repeated claim on this site and across the trade, and it is the one least often attached to a method. Our own guides and product pages describe poly-viscose, chambray and lightweight shirting as breathable dozens of times over. Every one of those statements is a structural inference from blend, yarn count, weave and cover, which is a reasonable thing to say and is not a measurement. Two mills can both call a cloth breathable and mean different things, and a buyer comparing them has nothing to compare.

The measurable part of it is air permeability: how readily air passes through the cloth under a stated pressure difference. It reaches a spec sheet as a flow rate, and it is testable on the actual lot rather than argued from the construction. The methods a specification names are ISO 9237 and ASTM D737. Both clamp a specimen, pull air through a defined test area and report the rate, and both are only meaningful with the pressure difference written next to the figure, because a result taken at one pressure drop cannot be read against a limit written for another. The units differ between the two methods as well, so a figure with no method and no pressure beside it is not a specification, it is an adjective with a number attached.

Two limits are worth stating plainly. Air permeability is airflow only. It contributes to what a wearer calls comfort but it is not the whole of it, since moisture movement matters as much as air movement, and a cloth can test well on airflow and still feel clammy in a hot kitchen. And a number is a property of the lot that was cut and tested, not a permanent property of the quality, because a resin or water-repellent finish, a tighter sett or a heavier construction will all move it. If a programme cares about the figure, it belongs in the specification and in the pre-dispatch check, not only in the enquiry.

What we can and cannot do here is worth being straight about. We do not run an accredited laboratory of our own, so an air permeability figure on our cloth comes from a third-party laboratory test on the lot, arranged the same way as our other test reports. If a tender asks for one, ask for it as a numbered method with a stated pressure difference on the shipping lot, and treat any breathability claim without those two things, ours included, as a description rather than a result.

This is the same discipline as the abrasion section above. The property is real, the claim is common, and the only version of it a buyer can hold a supplier to is a numbered method on a stated lot. Related reading: summer and winter fabric weight, poly-viscose against cotton and shirting GSM and opacity.

A worked read of a real spec

Take Officer Choice: composition poly-viscose blend, 210-230 GSM, 150 cm width, plain or structured suiting weave, khaki/navy/olive plus custom shades, wash-fast and wrinkle-resistant. That reads as a mid-weight, durable, colour-stable suiting built for uniforms that must hold a line and a shade, exactly what a force or security buyer wants.

Building a spec from a swatch when you are changing supplier

The hardest version of reading a spec sheet is the one where there is no spec sheet. A buyer with a running uniform programme decides to change supplier, or the old supplier stops answering, and all that survives of the specification is cloth: a length in the store, a roll end, sometimes only a garment already in service. Everything on the sheet has to be worked backwards out of that.

Most of it can be recovered. Weave reads directly off the cloth under a lens, plain against twill against dobby. Ends and picks can be counted in a marked square and give you the construction. Weight comes off a cut disc on a balance. Width comes off a full roll edge to edge, and cuttable width off the same roll inside the selvedges, which is the number your cutting room actually uses. Yarn count can be approximated from the counted construction and the measured weight, closely enough to specify a like-for-like quality. Composition needs a laboratory, and it is worth doing properly, because a ratio guessed from handle is the single most common way a replacement cloth ends up behaving differently in wear.

Two things never come back. The finish recipe is one: whether a cloth was given a resin treatment, a softener, a particular calendering, and in what sequence, is not readable from the finished fabric, and the same construction finished two ways will handle and wash differently. The dye recipe is the other. A shade can be matched, closely and repeatably, but it is matched by lab dip against a physical reference and not reconstructed from the old mill's recipe. Accept that both are being rebuilt rather than copied, and the switch goes smoothly. Assume they transfer, and the first bulk lot is where you find out.

One trap specific to switching: match the shade to what the cloth looked like new, not to the garment on the table. A uniform in service for a year has faded, been washed dozens of times and picked up soiling, and matching to it locks in the wear rather than the colour. If the only reference is a worn garment, use an unexposed part of it, an inside seam allowance, a pocket bag, the underside of a collar, and say plainly to the mill that this is what is being matched.

• Send a physical swatch, never a photograph. Screen white balance and handset processing move a colour, and a photo can confirm weave, check repeat and roll condition but cannot approve a shade.
• Send it large enough to test: a piece that can be cut for composition, weight and a wash trial, not a corner clipping.
• Get composition done by an independent accredited laboratory and put the report with the swatch, so the new mill is quoting against a measured ratio rather than a claimed one.
• Ask the new mill for its nearest running quality first, before commissioning anything custom. A running construction that is close is faster, cheaper and more repeatable than an exact copy woven to order, and often the difference is invisible in the garment.
• Run a lab dip against the swatch, then a trial length, then bulk. Do not compress those three into two.
• File the approved reference under your programme name at the mill, so the next reorder is judged against it rather than against the last delivery.

Where the difference between the nearest running quality and a woven-to-order copy actually matters, custom production versus ready stock sets out what each one costs you in time and minimum quantity.

FAQ

Frequently asked questions

What is the most important number on a spec sheet?

There is no single one. Composition and GSM together tell you the most: the blend decides behaviour, the weight decides durability and warmth.

Why does fabric width matter?

Wider fabric fits more garment pieces per meter, so it changes how many meters a uniform needs and therefore the cost. Always compare fabrics at the same width, and check the figure on the product page: most of ours are 147 cm, several suitings are 150 cm, and the narrower shirting and lining cloths run 142, 91 or 89 cm.

What does a wash-fast finish guarantee?

That the colour is engineered to survive repeated laundering without significant fading. It is essential for any uniform washed frequently.

Where can I see full specs for your fabrics?

Every product page lists composition, GSM, width, weave, colours and finish, with a shade card available on request.

How do I know a wash-fast or wrinkle-resistant claim is real?

Ask what test the mill runs and against what standard, for example a numbered wash-fastness or shrinkage test on a swatch before and after a standard cycle. A mill that dyes and finishes in-house can back a claim with its own test results; a trader reselling finished cloth usually cannot.

What is the difference between plain, twill and dobby weave?

Plain weave is simple and even, twill has the diagonal line seen in trousers and structured suiting and drapes well, and dobby adds a subtle woven texture. The weave affects strength and drape as much as GSM does.

Can a mill reproduce my existing fabric from a swatch alone?

It can reproduce the construction closely: weave, ends and picks, weight, width and an approximate yarn count all read off the cloth, and composition comes back from a laboratory. It cannot reproduce the previous mill's finish recipe or dye recipe, because neither is readable from finished fabric. The shade is matched by lab dip against your swatch instead.

What should I send a new mill when I am switching supplier?

A physical swatch big enough to cut for testing, an independent composition report if you have one, your width and consumption requirement, and the end use. Photographs are useful for weave and check repeat and useless for shade, so they supplement a swatch rather than replace it.

My only reference is a uniform that has been worn for a year. What now?

Match to an unexposed part of it, an inside seam allowance, a pocket bag or the underside of a collar, and tell the mill that is what is being matched. Matching to the visible outer face locks a year of fading into the new order, so the replacement arrives correct against the wrong target.

A specification says 20,000 Martindale cycles. Is that the same as 20,000 double rubs?

No, and no conversion factor makes them comparable. Martindale cycles come from ISO 12947 or ASTM D4966, where the specimen is rubbed along a figure-of-eight path under a defined load. Double rubs come from ASTM D4157, the Wyzenbeek method, where the specimen is drawn back and forth across an abradant on an oscillating cylinder. The two put wear into the cloth differently, so a result on one cannot be evaluated against a limit written for the other. Where a specification quotes both figures for the same fabric, ask which one the technical evaluation will actually run against, and settle it before the bid rather than after.

Our tender asks for a breathability figure. What do we ask the mill for?

Ask for air permeability to a named method, either ISO 9237 or ASTM D737, with the pressure difference stated next to the result, tested on the lot being shipped rather than on a past sample. Say in the specification which of the two methods you will accept, because the two are not interchangeable and a result at one pressure difference cannot be read against a limit written for another. If the tender only says breathable with no method, that is not something any mill can be held to, and it is worth fixing in the document before bids come in.

Why does one abrasion figure look enormous next to another?

Usually because the larger figure was written for furnishing fabric. Upholstery specifications run into tens of thousands of cycles or double rubs, because a seat cover takes the same rub in the same place for years. Apparel and uniform methods stop at a much lower end point, since a garment fails at a cuff, an elbow or a seam long before a seat cover wears through. A uniform tender carrying an upholstery figure will read as unmeetable to every mill bidding on it, so it is worth raising as a specification query rather than treating it as a straight pass or fail line.