Sportswear colour fastness: which tests, which grades

Which colour fastness tests does activewear need?

Washing, rubbing and perspiration cover most activewear; add light fastness for products worn outdoors. Each exposure has its own method, and passing one says nothing about the others. US buyers and laboratories often use the AATCC counterparts. Choose one family per programme, because the conditions differ and results do not convert.

Colour fastness to chlorinated water (ISO 105-E03) matters only if the garment will be used in a pool. For a training tee, polo or set, the core is the first three rows of the table.

What does a grade of 4 actually mean?

It is a visual comparison against a grey scale, from 5 (no visible difference) to 1 (a large difference), with half grades in between. ISO 105-A02 is the scale for change in colour of the tested specimen; ISO 105-A03 is the scale for staining of the adjacent fabric.

In washing and perspiration tests the specimen is usually sewn to a multifibre adjacent fabric, a strip woven with bands of different fibres. ISO 105-C06 uses a version containing wool and acetate (DW) for tests at 40 °C and 50 °C, and one without them (TV) for some 60 °C tests and all hotter ones. Staining is graded strip by strip and the lowest grade decides: disperse-dyed polyester often stains the acetate and polyamide strips most.

Light fastness works differently. ISO 105-B02 compares fading with blue wool references, usually reported on a 1–8 scale, so a 4 for light is not the same as a 4 for washing.

Which grades should a buyer specify?

The buyer sets them, because the ISO 105 methods define the procedure and the grey scales, not a pass mark. Common starting targets are grade 4 for colour change after washing or perspiration, 3–4 or 4 for staining and 4 for dry rubbing. Wet rubbing is the result most often negotiated on deep shades: many buyers accept 3 and some accept 2–3 for very dark colours, while performance programmes ask for more.

Treat these as starting points to adjust by colour and end use, not industry rules. Write any shade-specific exception into the specification before bulk, rather than negotiating it after a failed report.

Why do dark polyester and nylon garments bleed?

Usually because unfixed or migrated dye sits on the fibre surface, where washing, sweat and friction can move it. Polyester is dyed with disperse dyes, and in deep shades the surface dye is normally stripped by reduction clearing; weak clearing lowers fastness. Heat applied later, in heat-setting, finishing or decoration, can draw dye back to the surface, which is why fabric tested straight after dyeing can pass while the finished fabric fails. Elastane takes up disperse dye but holds it poorly, so deep polyester-elastane shades need thorough clearing. Polyamide is dyed with acid dyes and is often after-treated with a fixing agent to improve wet fastness.

The same chemistry reaches the logo. On dark or bright polyester, dye can migrate into a white print or heat transfer straight away or gradually afterwards. Ask how the decorator blocks migration, for example with low-bleed inks, a blocking layer or a controlled press temperature, and include a decorated panel in the test plan.

How do you keep bulk shade consistent?

Approve a lab dip under named light sources, approve the first bulk lot against it, and keep the physical standard for every later lot. Agree the light sources before the first dip: D65 daylight plus the light the garments will be sold under, often a store fluorescent such as TL84. Colours that match under one source and differ under another (metamerism) are a common cause of rejection, and a dyehouse can only avoid it if it knows which sources count.

Many buyers add an instrumental check. ISO 105-J03 defines the CMC colour difference, which lets one numerical tolerance apply across different shades. Sets need extra care: a tee and shorts with the same colour name are often different fabrics, sometimes different fibres, and take dye differently, so approve them side by side. Cut each garment from one dye lot so panels match, and store the dated master swatch away from light.

SenLin matches colours to Pantone references through lab dips. Colour fastness tests, the laboratory and acceptance grades are agreed per order, and SenLin publishes no in-house test results.

What should the care label and test brief say?

The care label has to agree with the results. The US FTC Care Labeling Rule requires a reasonable basis for care instructions and a warning where a washing procedure consumers can reasonably be expected to use would harm the product or others washed with it; “wash with like colours” is a familiar example. A warning manages that risk, but it does not repair poor rubbing or perspiration fastness.

The test brief should list every test with its method, condition code and edition, and say which material is tested, because plain fabric is not enough for a decorated or colour-blocked garment.

• Specimens from bulk-dyed, finished fabric, not from the lab dip.
• Each decorated panel and contrast trim, including rib, binding and drawcord.
• Minimum grades for colour change, staining and rubbing, with shade exceptions written in.
• Cross-staining between panels, assessed on a composite specimen sewn from the adjacent colours.
• Light sources, instrumental tolerance and the master swatch reference for shade approval.