Added 2026-09-25 from trending overseas buyer search questions. We update this centre daily.
Colour fastness is a fabric's ability to keep its colour under use — through washing, rubbing, light exposure, perspiration and rain. Poor fastness shows up as fading, shade shift, or dye bleeding onto other garments. It is a performance property, verified by standardised lab tests and reported as a number, not something covered by chemical-safety certificates such as OEKO-TEX or GOTS.
Most fastness results are graded on the grey (gray) scale, a reference of paired grey chips from 1 (worst) to 5 (best), in half-step increments (1, 1–2, 2, 2–3, 3, 3–4, 4, 4–5, 5). The scale is standardised under ISO 105-A02 (colour change) and ISO 105-A03 (staining). In plain terms: grade 5 = no visible change; grade 4 = slight change, visible only on close inspection; grade 3 = moderate, noticeable; grade 2 = significant; grade 1 = severe failure.
A fastness report shows two separate numbers. Colour change rates how much the tested fabric itself faded or shifted from the original shade. Staining (sometimes called bleeding) rates how much dye transferred onto the adjacent white cloth. Always read both: a fabric can score 5 for change but only 3 for staining — meaning it did not fade, but it bled onto other clothes in the wash. A report that only says "Pass" without numbers is incomplete; ask for the numeric grade.
You rarely need all of them — specify by end use. A winter-coat lining does not need high light fastness; a swimsuit needs chlorine fastness instead.
For most EU and North American apparel programmes, grade 4 is the common minimum for wash and rub fastness. 4–5 is comfortably above requirement and seen as excellent. Lighter shades are often held to 4; darker shades (navy, black, burgundy) may be accepted at 3–4 because they are harder to fix. Light fastness follows the Blue Wool scale: curtains and displays typically need 5 or higher, automotive interiors 7+.
Dark colours need higher dye concentration to reach depth. At high concentration a portion of dye molecules stays unfixed inside the fibre and becomes the source of bleeding and crocking failure. Reliable mills manage this with dye-class selection, longer fixation time, fixatives and thorough after-washing — but buyers specifying dark colours should expect a higher dyeing cost and a lower achievable ceiling.
State the minimum grade per test and per end use in your technical specification before production, not in the QC conversation at the end. Ask the supplier for a third-party or in-house lab report that names the standard, the sample, and both the change and staining grades, matched to your bulk lot number. As an integrated woven mill with in-house yarn dyeing, weaving, fabric dyeing, printing and finishing, Nantong Huayuan controls fastness at the dye-class and fixation stage; the specific grade achievable for your fibre, dye and shade is confirmed per order — available on request.
On the 1–5 grey scale, 4–5 means the colour change or staining is barely perceptible — it sits between grade 4 (slight, visible only on close inspection) and grade 5 (no visible change). It comfortably passes most retail quality requirements.
"Colour change" rates how much the tested fabric itself faded or shifted from the original. "Staining" rates how much dye transferred onto the adjacent white cloth. Always check both — a fabric can score 5 for change but only 3 for staining, meaning it did not fade but bled onto other garments in the wash.
No. Wash, rub and perspiration fastness use the grey scale (1–5). Light fastness uses the separate Blue Wool scale (1–8); curtains and displays typically need 5 or higher, automotive interiors 7+.
For most EU and North American apparel programmes, grade 4 is the common minimum for wash and rub fastness. Lighter shades often 4, darker shades 3–4 may be accepted. State the minimum per end use in your technical specification before production, not at final QC.