The claim, the colour and the customer in motion

The situation

One page, four claims. Tarnhow's approved hangtag for TG-620 says:

Four-way stretch. Sweat-wicking. UPF 50+. Squat-proof.

And one shade approval, signed on a flat swatch in a light box on 20 December.

Everything on that page is true of a flat, dry, clean, unstretched specimen lying on a bench. A tight is worn stretched, wet, dirty and moving. This lesson is the gap between the test condition and the use condition. In this category, that gap is where almost every remaining complaint lives.

The colour that only fails when it is stretched

Start with the one a cotton buyer has never met.

TG-620 is Peat, a deep brown-black, on a polyamide and elastane knit. Polyamide takes acid dyes. Elastane takes them badly and gives most of it back in the first washes. So in almost every stretch fabric the elastane is effectively undyed, sitting inside a coloured cloth.

Flat, you never see it. Stretch the cloth and the loops open, the pale filament shows through, and the shade reads lighter. This is not a fastness failure — nothing has moved and nothing has bled. It is the fabric doing what it was built to do. And it appears exactly where the garment stretches most: the seat, the knee, the back of the thigh.

Serimen measured it on bulk against the sealed standard. The sealed standard is the signed swatch everything else is compared to.

Tarnhow's limit is 1.0. The fabric passes flat and fails at the extension a full squat actually applies to the seat. And the shade band was approved flat, in December, on a swatch.

The fix costs USD 240 and is a piece of hardware: a stretch frame in the light box. For any fabric above about 12% elastane, the sealed standard and every bulk assessment are read in two states — relaxed, and at a stated extension — and the tolerance is set separately for each. Course 3.3 covers colour approval. The line this category adds is that a shade band on an elastic fabric that names only one state has approved half a colour.

Two neighbours of this problem, named so you look for them:

• Staining between panels. The Quartz waistband facing sits against the Peat body, wet with sweat. Perspiration fastness is tested to ISO 105-E04 in acid and alkaline, and polyamide stains readily. On bulk the Quartz picked up to grade 3-4 against a specification of 4. And E04 had been run on each fabric alone, never on the two in contact — which is the only way this garment is ever worn.
• Sublimation. Disperse dye on polyester moves as a vapour under heat. That puts every heat press, heat-transfer label and hot container in the path of your colour. Course 3.4 covers it in full. On this garment it matters because lesson 4's bonding press is a heat source sitting directly on a colour join.

And one honest gap: sunscreen. It is the single most common cause of colour and yellowing complaints on light activewear, and there is no method for it in any standard test package. If it matters to your range, you write your own — a stated product, a stated dose, a stated exposure — and you say in the specification that it is a house method, so nobody quotes it as a standard.

Reading the four claims against their tests

UPF means ultraviolet protection factor: how much of the sun's ultraviolet the fabric blocks. That line is worth the arithmetic, because it is the one with a real number on the tag. Tarnhow's laboratory measured the same fabric three ways:

The tag is defensible about a fabric and indefensible about a garment. The standard itself says so: the fabric method is one part of EN 13758, and the rules for what a garment may claim are a separate part, with requirements of their own. Two ways out, both honest:

• Specify the property at extension. Holding 50+ at 30% extension needs a tighter construction: 265 gsm instead of 250, USD 0.25 a garment, USD 6,000 across the order.
• Drop the claim. A training tight is worn under nothing and sold on fit. The sun claim earns nothing there.

Tarnhow dropped it on the tight and kept it on the top, which is worn outdoors, with the fabric specified and tested at extension. That is the decision, and it took one table to make.

"Compression" deserves its own warning. It is the most-used word in the category, and it has no consumer-textile standard behind it. Medical compression hosiery has one; a sports tight does not. So a compression claim is a marketing word until somebody writes a number. And the number is the one lesson 1 asked for and lesson 2 put a floor under:

Retractive force at 40% extension, 50 mm strip: 7.5 to 9.5 N as received, and not below 6.5 N after 20 wash cycles.

The fit session that only tested standing still

Tarnhow added four movements to its activewear fit sessions, and recorded the measurement in the moved position as well as standing. What they found on the first session:

Grin-through is the pale undyed filament showing when the loops open.

Take the waistband roll, since it is the one the customers wrote about. Three priced options:

The second misses the ship date. The third fixes one return and creates the opposite one. Tarnhow took the first, and it is the answer most often available: a fit failure in movement is usually solved by geometry rather than by fabric, and geometry is cheap and has no lead time.

Tarnhow's own measured figure is that fit-related returns run at 12.6% on its tights against 8.1% on its tops. Course 18.5 covers what a return actually costs a business. What this category contributes is the cause. The tights are the garment whose fit is decided by movement, and movement is the one thing the approval process never looked at.

Adding four movements to a fit session costs six minutes. That is the whole intervention.

Act as a performance-textile technologist who has had to defend claims to a retailer's legal team. I want every claim on this garment audited against evidence. Facts: brand [BRAND], style [STYLE], garment type [TYPE], markets it is sold in [LIST], fabric [CONTENT, CONSTRUCTION, WEIGHT], elastane content [PERCENT], colourways [LIST], and any contrast panels or trims in contact with the body fabric [DESCRIBE]. The hangtag and product page say: [PASTE EVERY CLAIM WORD FOR WORD]. Test reports I hold: [LIST EACH ONE WITH ITS METHOD, THE STATE THE SPECIMEN WAS IN, AND THE RESULT]. Do the following. First, take each claim in turn and name the test that would support it, the state the specimen is tested in, and the condition of real use that the test excludes. Second, tell me which of my claims currently has NO test behind it at all, and say plainly whether a standard exists for it. Third, for any claim measured on a fabric, tell me whether a garment-level requirement exists separately, and whether my claim needs it. Fourth, list the colour risks specific to this construction: shade read under extension, staining between panels in contact under sweat, dye movement under any heat process the garment passes through, and anything the wearer puts on their skin for which no method exists. Say which of these my current test package covers and which it does not. Fifth, propose the cheapest honest fix for each failing claim — restate the claim, retest in the used condition, change the fabric with a cost per garment, or drop the claim — and recommend one. Sixth, write the revised wording for the hangtag. Do not invent a standard number or an edition year; if you are unsure of one, name the standard without it and say so.