Overview
CEN ISO/TR 9241-312:2022 (identical to ISO/TR 9241-312:2020) is a technical report in the ISO 9241 ergonomics series that summarizes recent research on the readability of electrophoretic displays (EPD) - commonly known as electronic paper displays. The report provides an evidence-based overview and practical information for evaluating readability of EPDs and for defining the context of use (illumination, tasks, device types, user populations).
Key topics
- Readability and legibility for electronic paper displays: literature review covering perceptual factors and prior studies.
- Evaluation methods and experimental setups: recommended equipment, participant considerations, tasks, and measurement approaches used in readability studies.
- Illumination conditions: evaluation of readability across multiple lighting levels (the report examines 14 levels of illumination) and discusses minimum illuminance verification.
- Subjective assessment methods: use of Visual Analogue Scales (VAS) and other subjective measures for perceived readability.
- Character size and typography: contribution of character sizes to readability on mobile and tablet EPDs.
- Contrast and display performance: effects of contrast ratio on readability under different lighting conditions.
- Long-term reading effects: impact on visual function and subjective symptoms during extended reading sessions.
- Special populations and accessibility: considerations such as cataract cloudiness influencing EPD readability.
- Context of use: guidance on specifying real-world conditions (device orientation, ambient lighting, viewing distance, user tasks).
Practical applications
This report is useful for professionals involved in the design, testing, procurement and regulation of devices that employ electrophoretic displays, including:
- Display and device manufacturers designing e-readers, e-paper signage, and low-power mobile devices.
- UX / human factors engineers conducting readability testing and user studies.
- Accessibility specialists specifying readable text sizes and contrast for older adults or visually impaired users.
- Product managers and procurement teams defining acceptance criteria and minimum lighting/contrast requirements.
- Standards developers and test labs developing test protocols based on documented experimental methods.
Practical uses include establishing test conditions, choosing subjective and objective readability metrics, and informing design decisions such as font size, contrast targets, and lighting recommendations for EPD-based products.
Related standards
- Part of the ISO 9241 series (ergonomics of human-system interaction).
- Published by ISO and adopted by CEN as CEN ISO/TR 9241-312:2022 without modification.
Keywords: electrophoretic displays, electronic paper displays (EPD), readability, ISO/TR 9241-312, ergonomics, legibility, illumination, contrast ratio, character size, VAS evaluation.