Overview
EN ISO 10215:2018 - Anodizing of aluminium and its alloys - Visual determination of image clarity of anodic oxidation coatings - Chart scale method (ISO 10215:2018) is a CEN-endorsed visual test method for assessing the image clarity of anodic oxidation (anodized) coatings on aluminium and its alloys. The standard specifies a chart scale (optical combs) and a lightness scale to quantify image clearness, image distortion and haze value on flat, reflective surfaces. It is intended for visual evaluation where instrumental methods are not used.
Key topics and requirements
- Scope: Applies only to flat surfaces capable of reflecting the chart pattern; defines symbols and units for image clarity (C), image clearness, image distortion (I) and haze (H).
- Principle: Visual estimation of three properties (clearness, distortion, haze) from the reflected image of a chart scale. The combined result yields an image clarity value.
- Chart scale (optical combs): Grades 1–11 with defined black/white line widths. Grades range from wider lines (Grade 1) to very fine lines (Grade 11); widths (mm) are specified in the standard (e.g., Grade 1 = 2.00 mm down to Grade 11 = 0.125 mm).
- Apparatus: Standardized chart scale, an observation box with controlled white light, lens and diffuser, and a lightness scale. The observation box positions the chart, specimen and viewer to standardize visual conditions.
- Test specimen: Sampling, specimen size and pre-test treatment are specified to ensure repeatability.
- Result expression and reporting: Procedures to calculate/express image clarity (C) and to report test conditions and outcomes are defined.
Applications and users
EN ISO 10215:2018 is used for quality control, acceptance testing and comparative evaluation of anodic oxidation coatings where appearance and reflective quality matter. Typical users include:
- Anodizing and surface‑treatment laboratories performing routine visual quality checks.
- Quality assurance / QC inspectors in aluminium fabrication and finishing plants.
- Materials engineers and specifiers developing finish requirements for components.
- Architects, façade and lighting designers concerned with reflective appearance of anodized panels.
- Manufacturers of automotive trim, consumer electronics and decorative metalwork where image clarity impacts aesthetics.
Practical uses include visual grading of mirror-like finishes, batch acceptance of anodized sheets or extrusions, and troubleshooting surface preparation or coating process issues that cause haze or distortion.
Related standards
- ISO 10216 - Instrumental method using optical combs (recommended when higher accuracy or dispute resolution is required).
- ISO 7583 - Terms and definitions for anodizing of aluminium and its alloys.
Using EN ISO 10215:2018 helps organizations standardize visual assessment of anodized finishes, improving consistency in specification compliance and customer-facing surface quality.