Colour Fastness to Water and Seawater Testing

Colour fastness to water, seawater, and chlorinated water evaluates the resistance of dyed textiles to colour change and staining under immersion conditions — critical for swimwear, beachwear, outdoor upholstery, water sports textiles, marine textiles, and any fabric exposed to rainfall, dew, or liquid water contact during use. ISO 105-E01 (water fastness): specimen plus multifibre adjacent fabric immersed in distilled water at 20°C, loaded in perspirometer frame at 4.5 kPa, 4 hours at 20°C — assesses dye mobility in pure water (relevant to wet weather apparel). ISO 105-E02 (sea water fastness): artificial seawater (30 g/L NaCl, adjusted to pH 8.0) substituted for distilled water, otherwise identical to E01 — NaCl promotes ion-exchange displacement of ionically bonded dyes, giving 0.5–1.0 grade lower result than E01 for acid dyes on protein fibres and direct dyes on cotton. ISO 105-E03 (chlorinated swimming pool water fastness): specimen immersed in water containing 50 mg/L active chlorine (sodium hypochlorite solution), pH 7.5 ±0.2, 20°C, 1 hour agitation — chlorine at pool concentration oxidatively bleaches reactive and vat dyes on cotton, degrading grade 4–5 washing fastness dyes to grade 2–3 after single pool exposure. AATCC TM107 (water fastness), AATCC TM106 (seawater fastness) are equivalent North American methods. Chlorinated pool water specification: swimwear dyed with reactive dyes grade 2–3 (moderate) versus vat dyes grade 4–5 (excellent) after ISO 105-E03 — vat dyes preferred for competitive swimwear and pool-use apparel despite higher cost ($3–8/kg versus $1–3/kg reactive).