Overview - ISO 11642:2012 (Colour fastness to water for leather)
ISO 11642:2012 defines a reproducible laboratory method to determine the colour fastness to water of leather at all stages of processing. Developed in cooperation with IULTCS, the standard covers both finished and unfinished leathers, including a procedure to test leathers with the finish intentionally broken. The method assesses both the change in leather colour and staining of adjacent fabrics after controlled wetting and pressure exposure.
Keywords: ISO 11642:2012, colour fastness to water, leather testing, waterfastness, IULTCS, perspirometer.
Key topics and technical requirements
- Principle: Soak leather and specified adjacent fabric in demineralized water, assemble as a composite, apply uniform pressure and heat, dry, then assess colour change and staining.
- Apparatus and materials: stainless-steel frame with a weight-piece (~5 kg) to give 12.5 ±1.0 kPa pressure; glass or acrylic plates (~1.5 mm thick); oven at 37 °C ±2 °C; vacuum-desiccator and pump (evacuate to ~5 kPa within 4 min); demineralized water (ISO 3696 grade 3); abrasive paper P180; grey scales and/or instruments.
- Specimens: typical test specimen ~100 × 40 mm (or larger for upholstery); if finish is broken, roughen using a 1 kg weight with ~10 to-and-fro cycles over ~100 mm then cut specimen from the roughened area.
- Procedure: vacuum-wet specimens (three vacuum cycles), assemble with adjacent fabric(s), preheat weight-piece, load and tilt to drain, then oven-load for 180 min ±10 min at 37 °C. Dry hanging with specimens attached at one corner.
- Evaluation: visual assessment under D65 illumination using ISO grey scales for staining (ISO 105‑A03) and change in colour (ISO 105‑A02), or instrumental assessment (ISO 105‑A04/‑A05) if staining is even.
- Precision & reporting: typical inter-person visual precision ±0.5 grey-scale units. Test report must reference ISO 11642 and include leather type, surface tested, finish status, grey-scale ratings for each adjacent fibre, and any procedure deviations.
Applications and who uses it
- Quality control in tanneries and leather finishing operations.
- Compliance and durability testing for footwear, upholstery, garments, and leather accessories.
- Independent textile and leather testing laboratories and R&D teams evaluating dye migration, finishing performance, and product specifications.
- Product designers and procurement professionals requiring verified waterfastness data for materials selection.
Related standards
- ISO 105-A01, A02, A03, A04, A05 (colour fastness principles, grey scales, instrumental methods)
- ISO 105-F01–F10 (adjacent fabric specifications)
- ISO 2418 (sampling location for leather)
- ISO 3696 (water for analytical use)
This concise method ensures consistent, comparable data on leather waterfastness for product development, acceptance testing, and regulatory documentation.