EN ISO 11642:2025 – Leather: Colour Fastness to Water

EN ISO 11642:2025 – Leather: Colour Fastness to Water

Full title: Leather – Tests for colour fastness – Colour fastness to water (ISO 11642:2025)

Published by: European Committee for Standardization (CEN) in collaboration with ISO and IULTCS

ICS Classification: 59.140.30 – Leather and furs

Purpose:

This standard establishes a uniform method for evaluating how leather resists colour changes and staining when exposed to water. It ensures consistent, reproducible assessment across all leather types and stages of processing, supporting quality control, product development, and regulatory compliance.

Scope and Application

EN ISO 11642:2025 applies to:

All types of leather: raw, semi-finished, and finished

All stages of processing: tanning, dyeing, finishing

Objective: Measure colour fastness to water, including both colour change of the leather itself and staining of adjacent fabrics

Industries and users:

Leather manufacturers

Quality assurance laboratories

Product development and R&D teams

Regulatory compliance bodies

Test Principle

Leather samples and adjacent fabric specimens are soaked in demineralized water (ISO 3696 compliant).

A composite test piece is assembled under controlled pressure using a calibrated frame.

Samples are incubated at a set temperature, allowing water exposure to simulate real-world conditions.

After drying, colour changes and staining are evaluated either visually or instrumentally using standard grey scales.

Outcome:

Provides objective assessment of leather water fastness

Detects both bleeding/dye migration and direct colour change

Testing Apparatus and Materials

Apparatus required:

Apparatus Function

Stainless steel frame with calibrated weight Applies uniform pressure to sample assembly

Glass or acrylic plates Keeps samples flat and ensures consistent contact

Oven or controlled incubator Maintains specified temperature for water exposure

Vacuum desiccator Optional, for controlled drying

Grey scales for colour evaluation Quantitative visual comparison of colour change and staining

Materials:

Demineralized water (ISO 3696 compliant)

Adjacent fabrics (representing various fibre types for staining assessment)

Sample Preparation

Leather can be tested with finish intact or mechanically abraded to simulate wear.

Specimen dimensions and orientation are specified to ensure reproducibility.

Adjacent fabrics are prepared according to fibre type and size requirements to monitor staining.

Notes:

Samples must be conditioned under standard laboratory temperature and humidity prior to testing.

Multiple replicates are recommended for statistical reliability.

Evaluation and Reporting

Assessment Methods:

Visual assessment using internationally recognized grey scales for:

Colour change

Staining intensity on adjacent fabric

Instrumental evaluation (colorimeter or spectrophotometer) to improve precision

Reporting includes:

Leather type and finish

Sample preparation details

Test conditions (temperature, pressure, water volume)

Colour change rating and staining rating

Any abnormal observations

Rating scales: Grey scales typically range from 1 (poor) to 5 (excellent), with higher values indicating better water fastness.

Applications

(1) Quality Control in Leather Manufacturing

Ensure finished and semi-finished leather meets water resistance specifications

Prevent customer dissatisfaction due to dye bleeding or colour change

(2) Product Development and R&D

Evaluate new tanning, dyeing, or finishing processes

Optimize formulations to improve water fastness while maintaining desired leather aesthetics

(3) Industrial and Commercial Performance Verification

Automotive interiors, footwear, upholstery, and fashion accessories

Prevent colour degradation under normal water exposure

(4) Regulatory and Compliance Testing

Standardized, reproducible results for adherence to international trade regulations

Supports product certification and quality benchmarking

Related Standards

Standard Relevance

ISO 7906 General principles for colour fastness testing of leather

ISO 2418 Specimen positioning and preparation for leather testing

ISO 105 series (A02, A03, A04, A05, F01-F10) Textiles – colour fastness tests, grey scale ratings and adjacent fabric specifications

ISO 3696 Demineralized water specification for analytical use

EN ISO 11642:2012 Previous version, for reference and comparison

These related standards support accurate, reproducible testing and ensure cross-industry comparability.

EN ISO 11642:2025 provides:

A clear, standardized method for measuring leather colour fastness to water

Applicable to all leather types and production stages

Reliable evaluation framework using visual and instrumental grey scales

Essential tool for quality control, R&D, and regulatory compliance in the leather industry

Outcome: Leather manufacturers and laboratories can confidently assess water resistance, minimize colour defects, and optimiz product durability.

Testing Instruments Required for EN ISO 11642:2025

EN ISO 11642:2025 establishes a standardized method to evaluate leather’s resistance to colour change and staining when exposed to water. Accurate and reproducible testing requires specific instruments and controlled conditions.

1. Core Testing Instruments

Instrument	Purpose
Pressure Device / Stainless Steel Frame with Calibrated Weights	Applies consistent pressure to the wet leather and adjacent fabric composite, ensuring uniform contact during testing.
Glass or Acrylic Plates	Supports samples, keeps them flat, and maintains uniform pressure and water exposure.
Temperature-Controlled Oven / Incubator	Maintains required temperature for water exposure and drying, ensuring standardised test conditions.
Vacuum Desiccator (optional)	Used for controlled drying to remove residual moisture and prevent interference with colour assessment.
Grey Scale / Standard Colour Card	Provides a visual reference for evaluating colour change and staining on adjacent fabrics.
Spectrophotometer / Colorimeter	Instrumental measurement of colour difference (ΔE), enhancing objectivity and accuracy.

2. Auxiliary Equipment and Materials

Instrument / Material	Purpose
Conditioning Chamber / Climate-Controlled Humidity Chamber	Prepares leather samples to standard temperature and humidity prior to testing.
Precision Balance	Ensures accurate weight measurement for samples and calibration weights.
Graduated Cylinders / Beakers / Water Tanks	Measures and maintains required volumes of demineralized water (ISO 3696 compliant).
Laboratory Water Bath (optional)	Maintains precise temperature for pre-soaking or sample immersion.
Adjacent Fabrics (cotton, polyester, etc.)	Evaluates dye transfer and staining from leather to standard textile substrates.

3. Standard Water and Chemicals

Demineralized / Distilled Water, compliant with ISO 3696

Buffer solutions or mild detergents, if required by leather treatment

4. Laboratory Environment Requirements

Ambient temperature: 20–25°C

Relative humidity: 50 ± 5% RH

Good laboratory ventilation and water/chemical safety precautions

5. Selection Considerations

Pressure Device / Frame: Adjustable weights for consistent, repeatable pressure

Grey Scale / Spectrophotometer: Internationally recognized standards, proper resolution and color space

Oven / Drying System: Temperature stability ±1°C, uniform heating

Water Quality: ISO 3696 compliant to avoid impurities affecting results

Sample Holder Size: Compatible with various leather sizes and adjacent fabrics

2026-01-04 15:48