Overview
EN ISO 105-A03:2019 is an international standard established by CEN and ISO that specifies the grey scale methodology used to assess staining in adjacent fabrics during colour fastness testing. This standard provides a precise colorimetric specification of the grey scale as a permanent, reproducible reference for assessing and comparing staining levels on textiles. It is critical for maintaining consistent quality control across textile manufacturing and testing processes.
The standard replaces the previous version EN 20105-A03:1994 and incorporates technical updates including allowance for grey and black sleeves during testing and tighter tolerances for colorimetric values.
Key Topics
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Grey Scale Definition
The grey scale consists of pairs of non-glossy chips or swatches in white and neutral grey colors, covering colour fastness ratings from 5 (no staining) to 1 (severe staining). The scale visualizes perceived colour differences that correspond directly to fastness ratings.
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Colourimetric Specification
The standard provides detailed colorimetric data, using the CIELAB color space and ISO/CIE 11664-1 (10° observer, illuminant D65), ensuring objective and reproducible measurement of staining contrasts.
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Scale Variants
There are 5-step and augmented 9-step grey scales, with the latter including half-step intervals (e.g., 4-5, 3-4) for more nuanced assessment of colour staining.
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Test Procedure
Samples are compared side by side under controlled lighting (600 lux, natural sky light or equivalent) against a neutral grey background. Masking materials matching the sleeve colors are used to avoid visual bias.
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Rating Assignment
The degree of staining is rated according to the visual match between the tested fabric and the grey scale chips. Intermediate ratings are assigned when differences fall between two standard steps.
Applications
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Textile Quality Control
EN ISO 105-A03:2019 is essential for textile manufacturers and quality assurance laboratories to consistently evaluate staining that occurs during colour fastness tests, such as rubbing, washing, or exposure to light.
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Product Development and Compliance
Textile designers and developers use this grey scale method to assess product durability and ensure compliance with international quality standards before market release.
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Standardization and Certification
This standard supports certification processes by providing a universally accepted method to compare colour staining effects across different labs and regions.
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Research and Testing Laboratories
Testing facilities use the grey scale as a reference for training, validation, and calibration of equipment and personnel in colour fastness assessment.
Related Standards
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ISO 105-A01 – General principles for colour fastness testing
Provides foundational testing concepts and procedures relating to colour fastness assessments.
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ISO 105-J03 – Calculation of colour differences
Details methodologies for quantifying colour differences, complementing the visual grey scale method.
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ISO/CIE 11664 Series – Colorimetry standards
Defines observer data and illuminant parameters used in the colorimetric evaluation prescribed by EN ISO 105-A03:2019.
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ISO 105 Series Overall
A comprehensive collection of standards covering various aspects of textile colour fastness testing, with part A03 focusing specifically on staining assessment using the grey scale.
By following EN ISO 105-A03:2019, textile professionals ensure accurate, repeatable, and internationally harmonized assessment of colour staining-an important measure of fabric durability and consumer satisfaction in the global textile industry.