Overview
EN ISO 473:2020 (ISO 473:2019) - "Lithopone pigments - General requirements and methods of testing" is a CEN-adopted international standard that specifies the required characteristics, labelling and laboratory test methods for lithopone pigments. It covers three commercially important lithopone types: lithopone 20%, 30% and 60% (zinc sulphide content expressed approximately as % ZnS, balance mainly barium sulphate). The standard harmonizes definitions, sampling, testing procedures and reporting to support quality control, trade and regulatory compliance in the pigments and coatings industries.
Key topics and technical requirements
- Scope and definitions: Clear classification of lithopone types (20 %, 30 %, 60 %) and terminology consistent with ISO pigment vocabularies.
- Marking and labelling: Requirements for identifying lithopone content (20/30/60 % ZnS) on packaging and documentation to avoid transport and clearance disputes.
- Required characteristics and tolerances: Specifies the physical and chemical characteristics a lithopone pigment must meet (see Table 1 in the standard) and the agreed sample concept for compliance testing.
- Sampling: Reference to ISO 15528 for paint and raw material sampling; defines how to obtain representative test samples.
- Analytical test methods:
- Determination of barium sulphate and total zinc content - includes two methods (Method A and new Method B).
- Method B (Na EDTA titration): introduced for direct titration of total zinc - noted as easier, faster and reliable compared with the older potassium hexacyanoferrate method.
- Determination of zinc oxide content and other standard pigment tests (volatile matter, water solubility, oil absorption, hiding/lightening power) by referencing general ISO test methods (ISO 787 series).
- Test reporting: Required content of laboratory test reports to ensure traceability and consistent interpretation.
Applications and users
This standard is essential for:
- Pigment manufacturers and suppliers - to certify product quality and label compositions correctly.
- Paint, coatings and plastics formulators - for raw-material specification, batch acceptance and performance prediction.
- Quality control and analytical laboratories - for standardized test methods and reporting.
- Procurement, regulatory and customs authorities - to resolve classification, transport and compliance issues.
Practical uses include supplier contracts, incoming goods inspection, production quality assurance, product data sheets and dispute resolution.
Related standards
- ISO 787 series (general methods of test for pigments and extenders)
- ISO 15528 (sampling for paints and raw materials)
- ISO 18451 series (pigment terminology)
These normative references provide complementary sampling, glassware and analytical procedures cited within EN ISO 473:2020.
Keywords: lithopone pigments, EN ISO 473:2020, ISO 473:2019, testing methods, Na EDTA titration, zinc sulphide, barium sulphate, pigments and extenders, paint raw materials.