EN ISO 7759:2010 PDF

Overview

EN ISO 7759:2010 specifies a standardized method for measuring the reflectance characteristics of high‑gloss anodized aluminium surfaces using a goniophotometer or an abridged goniophotometer. The method characterizes visual appearance by quantifying specular and scattered reflection components from a narrow-source beam at a 30° angle of incidence. It is suitable for other high‑gloss metal surfaces but is not intended for diffuse‑finish metals and does not measure colour.

Key topics and technical requirements

• Measurement principle: Illumination at 30° incidence; reflected light measured at specific receiver angles to derive multiple appearance metrics.
• Primary appearance metrics:
  • Specular reflectance (Rs) - measured at the specular angle (30°).
  • Distinctness of reflected image (Ri) - derived from near‑specular measurements (30° ± 0.3°).
  • Narrow‑angle haze (Hn) - measured at ±2° from specular (≈28° or 32°).
  • Wide‑angle haze (Hw) - measured at ±5° from specular (≈25° or 35°).
  • Diffuseness (Rd) - measurement 15° away from specular (≈45°).
  • Directionality (Dh) - ratio of narrow‑angle haze measured parallel and perpendicular to surface texture (rolling/extrusion direction).
• Apparatus: Full goniophotometer or abridged type with fixed 30° incidence and defined receiver windows; rotatable clamp for specimen positioning; calibrated reflectance standards (including evaporated aluminium on glass); optional neutral density filters for very high specularity.
• Calibration & conditions: Geometric and spectral conditions, voltage regulation (instrument supply stability), and calibration against certified standards are specified. Precision and accuracy notes are provided (see Annex A).

Applications

• Quality control and acceptance testing of anodized aluminium finishes in automotive, architectural, appliance and decorative industries.
• Comparative appearance matching for components that must visually match across batches or joining parts.
• Specification and verification of surface-finish performance for suppliers, anodizers and coating laboratories.
• Research and development of surface treatments where directional reflectance and haze influence perceived gloss.

Who should use this standard

• Materials and surface‑finish engineers
• Anodizing and metal finishing laboratories
• OEMs, architects and specifiers requiring reproducible appearance metrics
• Test labs performing optical characterization of metallic finishes

Related standards and notes

• Normative reference: CIE 38:1977 for radiometric/photometric characteristics.
• EN ISO 7759:2010 supersedes earlier EN 12373‑13 editions; consult annexes for instrument precision details.

Keywords: EN ISO 7759:2010, anodizing, anodized aluminium, goniophotometer, reflectance measurement, specular reflectance, haze, distinctness of image, surface appearance.