Overview
EN ISO 18451-2:2018 (ISO 18451-2:2018) defines a standardized classification of colouring materials (pigments, dyestuffs and extenders) according to both colouristic and chemical aspects. Adopted by CEN, this part of the ISO 18451 series applies to manufacturers, suppliers and consumers of colouring materials and provides a common terminology and classification framework used across paints, coatings, inks, plastics, textiles, ceramics and some food and ceramic dyestuff examples.
Key topics
- Scope and normative references
- Applies to the colouring-materials industry and end users; refers to ISO 18451-1 for general terms.
- Terms and definitions
- Uses definitions from ISO 18451-1 to ensure consistent vocabulary across the series.
- Classification by colouristic aspects (Clause 4)
- Classifies inorganic and organic materials by optical behaviour:
- White pigments (light scattering independent of wavelength)
- Coloured pigments and dyestuffs (wavelength-dependent absorption + scattering)
- Black colouring materials (broadband absorption)
- Effect pigments (metallic, nacreous, interference effects)
- Luminous materials (fluorescent and phosphorescent)
- Includes examples with Colour Index (C.I.) references where applicable.
- Classification by chemical aspects (Clause 5)
- Organizes materials according to chemical families and composition (inorganic vs organic; common extenders are included).
- Practical notes and limitations
- Examples given for ceramics and food dyestuffs; some inorganic dyestuffs are mentioned but not fully classified when excluded from ISO/TC 256 scope.
- Colour Index designations are illustrative; collective designations may map to multiple C.I. entries.
Applications
- Procurement & specifications: Use the classification to write unambiguous product specs and purchase requirements.
- Product development & formulation: Helps formulators choose pigments/dyestuffs based on optical effect and chemical compatibility.
- Quality control & labelling: Standardized terminology improves QC procedures and product descriptions.
- Regulatory & compliance: Assists in compiling ingredient lists and documentation for industry or regulatory submissions.
- Cross-industry communication: Facilitates clear exchange of information among suppliers, manufacturers and end-users.
Who should use this standard
- Pigment, dyestuff and extender manufacturers
- Paints, coatings, ink and plastic formulators
- Ceramic and food colour technologists (for referenced examples)
- Procurement specialists, quality managers and standards bodies
Related standards
- ISO 18451-1 (Terminology - General terms) - normative reference for this part.
- Other parts of the ISO 18451 series for complementary terminology and classification guidance.
Keywords: pigments, dyestuffs, extenders, classification, colouristic aspects, chemical aspects, Colour Index, ISO 18451-2, effect pigments, fluorescent pigments.