Overview
ISO 6719:2010 - "Anodizing of aluminium and its alloys - Measurement of reflectance characteristics of aluminium surfaces using integrating-sphere instruments" - defines a standardized method to measure the luminous reflectance properties of anodized aluminium surfaces. The standard covers measurement of total reflectance, diffuse reflectance, specular reflectance (principal gloss), specularity, and diffuseness using integrating-sphere reflectometers. Note: the method is unsuitable for lighting reflectors.
Key topics and technical requirements
- Measurement principle: Use of an integrating-sphere reflectometer to collect and integrate reflected light flux from a specimen; photometric measurement simulates CIE standard illuminants and photopic response per ISO 11664-2.
- Apparatus geometry: Requirements for integrating-sphere construction and alignment (e.g., port area ≤ 5% of internal surface, entrance and specimen ports on same great circle, photometer at 90° ± 0.5°).
- Specular-included vs specular-excluded: Procedures for pivotable spheres or fixed-sphere types to obtain total (Qr) and diffuse (Qd) reflectance; typical specular measurement using 9° ± 1° incidence.
- Irradiation beam: Beam must be substantially unidirectional (rays within 3° of axis) and have specified annular dimensions to ensure accurate specular/diffuse separation.
- Calibration: Use of a white primary standard (pressed barium sulfate per ISO 7724-2), black-surface or light-trap zero standard, and a calibrated first-surface mirror as a working standard.
- Measurement protocol: Take three readings for each orientation (0°, 45°, 90° to rolling/extrusion direction) and average. Directionality and diffuseness calculations are specified with formulae in the standard.
- Reporting: Test report must reference ISO 6719, include instrument/manufacturer, preparation method, average total/specular/diffuse values, computed specularity/diffuseness and directionality, and test date.
Applications and practical value
- Quality control for anodized aluminium finishes (architectural panels, consumer goods, transport components).
- Characterization of surface gloss, specularity, and diffuseness in R&D and coating development.
- Acceptance testing for suppliers and contract specifications where surface reflectance properties affect appearance or performance.
- Correlating reflectance data with colorimetric and visual appearance control in manufacturing.
Who uses this standard
- Test laboratories and QA/QC teams in aluminium finishing plants
- Anodizing and coating manufacturers
- Materials scientists, product designers, and specifiers requiring reliable surface reflectance data
- Procurement and compliance engineers for appearance-sensitive products
Related standards
- ISO 7724-2 (colour measurement reference for barium sulfate primary standard)
- ISO 11664-2:2007 (CIE standard illuminants / colorimetry)
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