Colour Fastness to Rubbing Testing

Colour fastness to rubbing (crocking) evaluates the tendency of textile surface dye to transfer onto adjacent undyed fabric or skin through mechanical rubbing contact — a particularly critical fastness property for deeply dyed denim, dark-shade knitwear, printed fabrics, and any textile in close contact with upholstery or other textiles during wear and use. ISO 105-X12 (Crockmeter method, SDL Atlas Crockmeter, AATCC Crockmeter TM116) rubs a standard white cotton test cloth (50 mm × 50 mm) over the specimen surface for 10 cycles (20 rubs) under 9 N (±0.2 N) downward force on a 16 mm finger — both dry rubbing (undamped white cloth) and wet rubbing (white cloth wetted to 100±5% WPU of its mass in distilled water) tested on separate specimens. Wet crocking is consistently 0.5–1.5 grades lower than dry crocking for all dye classes due to lubricating water film facilitating dye particle mobilisation. Assessment of rubbing cloth: ISO 105-A03 grey scale for staining (grade 1–5, grade 5 = no staining). AATCC TM8 (equivalent to ISO 105-X12) used by North American buyers: identical instrument but cotton test cloth conditioned per AATCC standard conditions. Specifications: denim dry rubbing ≥ 4, wet rubbing ≥ 2-3 (even major denim brands accept 2-3 wet crocking because denim indigo ring dyeing fundamentally limits wet crocking performance); standard apparel dry ≥ 4, wet ≥ 3-4; upholstery dry ≥ 4-5, wet ≥ 3-4; automotive interior ≥ 4 dry and wet at 70°C (elevated temperature simulating hot car interior per BMW/Mercedes specification). Dye class crocking performance: reactive dyes on cotton dry 4–5, wet 3–4; vat dyes dry 4–5, wet 3–4; indigo (denim) dry 3–4, wet 1–3; pigment print dry 4–5, wet 3–4.