What is ISO 105 wash-fastness?

ISO 105 is a family of international standards for colour fastness. ISO 105-C06 is the wash-fastness test — a standardised soap solution, temperature, mechanical action and time. After the cycle, the specimen is graded for colour change and staining of adjacent multi-fibre strips using the ISO grey scale, 1 (very poor) to 5 (excellent).

What grade is required for retail?

Most European and North American sportswear retailers require ISO 105-C06 A2S or B2S with grade 4 minimum for colour change and grade 4 minimum for staining on the six-fibre strip. Some premium retailers demand 4.5. Sublimation on 100% polyester routinely achieves grade 5 because the dye sits inside the polymer, not on the surface.

Does sublimation ever fail wash-fastness?

Only when the sublimation was undercured (temperature or dwell time short) or when the fabric had a heavy softener finish that trapped un-sublimed dye at the surface. A correctly processed sublimation garment passes ISO 105-C06 at grade 5 for colour change and grade 4–5 for staining.

What about perspiration fastness?

ISO 105-E04 tests fastness to acid and alkaline perspiration — critical for sportswear next-to-skin. Grade 4 minimum is expected. Failure usually points to a dyeing issue with disperse or reactive dyes, not to decoration.

Quality Control · Sportswear Encyclopedia

Wash-Fastness Testing

Wash-fastness is where a kit's colour promise is proven. The test is unambiguous — a controlled cycle, a grey-scale card, a multi-fibre strip and a grade from 1 to 5. Here is how the lab actually runs it and what retail buyers demand.

Standard

ISO 105-C06

Wash-fastness

Cycle

A2S / B2S

40 °C / 50 °C

Grading

1 – 5

ISO grey scale

Retail pass

Grade 4+

Change & stain

How ISO 105-C06 runs

A 4 cm × 10 cm fabric swatch is stitched between two multi-fibre strips (six fibres — acetate, cotton, polyamide, polyester, acrylic, wool). The composite is placed in a stainless-steel canister with a standardised ECE soap solution, ten stainless-steel balls (A2S) or twenty-five (C2S) and heated to the target temperature in a rotating water bath.

Test	Temp	Time	Simulates
A1S	40 °C	30 min	Gentle domestic wash
A2S	40 °C	45 min	Standard domestic 40 °C
B2S	50 °C	45 min	Warm domestic wash
C2S	60 °C	30 min	Hot commercial wash
D3S	70 °C	30 min	Industrial laundering

Grading — colour change and staining

Colour change — original vs washed specimen judged under D65 daylight in a light box against the ISO 105-A02 grey scale for colour change.
Staining — each of the six adjacent fibres judged against ISO 105-A03 grey scale for staining. The lowest single-fibre grade is the reported staining figure.
Grade 5 — no visible difference. Grade 4 — slight change, still commercially acceptable. Grade 3 — visible change, retail reject. Grade 1 — heavy change, fabric fail.

Retail targets by product type

Match jersey (sublimated polyester) — colour change 5, staining 4–5.
Screen-printed cotton tee — colour change 4, staining 4.
DTF transfer on poly-cotton — colour change 4, staining 4.
Fleece hoodie with reactive-dyed cotton blend — colour change 4, staining 4.
Baselayer with disperse-dyed polyester — colour change 4–5, staining 4.

If a lot fails — what actually caused it

Sublimation under-cured — increase heat press dwell time by 10–15 seconds or verify calenders reach the setpoint.
Un-fixed reactive dye — repeat the wash-off stage in the dye house before decoration.
Excess softener — reduce softener concentration; heavy silicones can trap unbonded dye at the surface.
Disperse-dye migration — re-select dye class (high-energy disperse for sublimation-compatible polyester).
Wrong wash cycle recommended on the care label — align the label with the tested cycle.

Ship kits that survive the wash

Every colour and every decoration route we run is validated to ISO 105-C06 before bulk. Third-party reports (SGS, Intertek, Bureau Veritas) are available on request.

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