Colour Fastness to Washing Testing
category
Colour fastness to washing evaluates the resistance of dyed and printed textiles to colour change and staining of adjacent undyed fabrics under standardised washing conditions of temperature, detergent concentration, mechanical action, and wash time — the most commercially critical fastness test for all apparel and household textile products. ISO 105-C06 (accelerated domestic washing, SDL Atlas Launder-O-Meter or Gyrowash, 40-ball stainless steel test with SDC reference detergent ECE or IEC at specified concentration 4 g/L) covers test conditions A1S (40°C, 30 min), A2S (40°C with sodium perborate, simulates bleach), B2S (50°C), C2S (60°C), D3S (70°C), E2S (95°C) — condition selected to match care label claim. Multifibre adjacent fabric (DW, SDC: 6-strip composite — wool, acrylic, polyester, nylon, cotton, diacetate; or ISO 13934: similar composition) placed against specimen to assess cross-staining of each fibre type from dye transfer. Assessment: ISO 105-A02 grey scale for colour change (5 grades) and ISO 105-A03 grey scale for staining of each adjacent fabric strip (5 grades) under D65 illuminant at 1,000 lux, or instrumental ΔE*00. Minimum specifications by end-use: premium knitwear: colour change ≥ 4, staining ≥ 3-4; standard apparel: colour change ≥ 3-4, staining ≥ 3; workwear: colour change ≥ 3, staining ≥ 3; children's clothing (OEKO-TEX 100): colour change ≥ 4, staining ≥ 3-4. ISO 105-C10 (home laundering simulation, 5 wash cycles ISO 6330, full machine wash conditions) complements C06 accelerated test for after-wash appearance assessment.
Role
Washing fastness testing is the most commercially decisive colour fastness test for apparel — with washing fastness grade below 3-4 generating immediate retail rejection of entire dye lots, since consumers experience colour fading and cross-staining on the first home laundry cycle, causing returns and brand reputational damage that makes washing fastness specification enforcement the strictest quality control criterion in global fast fashion supply chain auditing.