ISO 9186-2:2008

Overview

ISO 9186-2:2008 - Graphical symbols - Test methods - Part 2: Method for testing perceptual quality - specifies a standardized empirical procedure to verify that the elements of a graphical symbol are readily identifiable by the intended user population. The method focuses on identifiability and perceptual quality rather than semantic comprehension: respondents name or describe the elements they see, and the outcome is reported as a correct identification percentage for each presentation size.

Keywords: ISO 9186-2, graphical symbols, perceptual quality, identifiability, symbol testing, visual angle.

Key topics and technical requirements

• Test principle: Show symbols to representative respondents at two or more presentation sizes (including a required 80 mm × 80 mm size) and score the percentage who correctly identify all symbol elements.
• Presentation sizes: Standard series - 80, 40, 28, 20, 14 and 10 mm square. These correspond (at 2 m viewing distance) to z-factors 25–200 and visual angles ≈ 2.30°, 1.15°, 0.80°, 0.57°, 0.40°, 0.29° respectively.
• Apparatus & print quality: Printed presentation with at least 24 dots/mm (600 dpi) resolution; symbols normally as black on white unless specific colours are required in application.
• Viewing conditions: Viewing distance (2 ± 0.04) m, eye-line ~90° to symbol plane; lighting between 95–105 lux measured at the symbol; daylight excluded.
• Respondent task & scoring: Respondents name or describe symbol elements (image content). Score is the proportion who correctly identify all elements. Organizations may set pass thresholds (example: high criterion for large size e.g. 90%).
• Pre-test submission: Submitter provides application details, image content description, minimum visual angle(s) for identifiability, confirmation of design conformance and EPS/TIFF artwork.

Practical applications and users

ISO 9186-2 is used to:

• Validate symbol legibility and element recognizability before standardization or mass deployment.
• Troubleshoot symbols that passed comprehension tests but show ambiguous element perception.
• Assess performance at small display sizes or long viewing distances (e.g., signage, vehicle panels, icons). Typical users:
• Standards bodies and submitters proposing symbols for ISO/CEN certification
• Graphic designers and sign designers
• Human factors and usability researchers
• Safety engineers, facilities managers and manufacturers of equipment or public information signage

Related standards

• ISO 9186-1 (Methods for testing comprehensibility)
• ISO 17724 (Graphical symbols - Vocabulary)
• ISO 22727 / ISO 7001 (public information symbol design guidance)
• ISO 3864-3 / ISO 7010 (safety sign design and standardization)

Using ISO 9186-2 helps ensure graphical symbols are not only meaningful but perceptually robust and fit for real-world viewing conditions.