CIE 249-2022 PDF

Full title and description

CIE 249:2022 — "Visual Aspects of Time‑Modulated Lighting Systems". This technical report from the International Commission on Illumination (CIE) addresses perceptual effects and measurement methods for lighting whose output varies in time (temporal light modulation), with emphasis on white‑light sources and solid‑state lighting technologies. It defines temporal light artefacts (TLAs), reviews visibility factors, presents both frequency‑ and time‑domain quantification methods and gives practical test guidance and recommendations for future work.

Abstract

This report documents definitions, measurement models and visibility quantification methods for temporal light modulation (TLM) and the resulting temporal light artefacts (TLAs) such as flicker, stroboscopic effects and phantom array. It gives an overview of factors that influence visibility, describes example implementations of visibility predictors (frequency‑domain and time‑domain), and provides practical guidelines for testing light sources and reporting results. The report is intended to harmonize terminology and measurement approaches used by manufacturers, test laboratories, researchers and regulators.

General information

• Status: Active, current.
• Publication date: 2022 (issued 1 January 2022, CIE publication number CIE 249:2022).
• Publisher: Commission Internationale de l'Éclairage (CIE), Division 1 (Vision and Colour).
• ICS / categories: Lighting and measurement of light (typical ICS classifications used for lighting and colour/measurement: 17.140 / 17.180.x — i.e., lighting, colours and measurement of light).
• Edition / version: CIE 249:2022 — first CIE Technical Report edition (2022).
• Number of pages: 51 pages (includes figures and tables as noted in the CIE publication summary).

Scope

The report covers visible effects produced by time‑modulated lighting systems based on white‑light sources. It addresses direct perception of temporal modulation (flicker, flashes) and interactions with observer or object movement in a lit environment. The scope excludes chromatic modulation where spectral changes rather than luminous intensity dominate (colour flicker models are not developed here), non‑visual/animal vision effects, and artefacts that arise only through capture or reproduction systems (e.g., TV recording). Acceptability limits are outside the report’s remit; the focus is on definitions, visibility prediction and measurement guidance.

Key topics and requirements

• Definitions of temporal light artefacts (TLAs) and related terminology.
• Review of psychophysical and physiological factors that affect visibility of TLM (observer, environment, stimulus parameters).
• Two complementary quantification approaches: frequency‑domain and time‑domain methods for visibility prediction.
• Three example implementations of visibility measures derived from the general methods.
• Practical test procedures and guidance for measuring TLM in light sources and luminaires.
• Recommendations for reporting, application‑specific applicability and directions for future research and standardization.

Typical use and users

This technical report is intended for lighting product manufacturers, control‑gear and luminaire designers, conformity testing and calibration laboratories, standards developers, lighting designers, regulatory and market‑surveillance bodies, and researchers studying perception, human factors and lighting quality. It is used to harmonize vocabulary, select measurement methods and implement test procedures for evaluating temporal aspects of lighting quality.

Related standards

Relevant and closely related documents include CIE TN 006:2016 (earlier technical note on definitions and measurement models for time‑modulated lighting systems), IEC and IEEE guidance on flicker and modulation measurement practices (examples cited in the report and industry publications), and other CIE/ISO/CIE joint publications on photometry, colour and lighting application standards (e.g., standards addressing lighting of workplaces and spectroradiometric measurement methods). Users commonly consult the cited IEC/IEEE documents alongside CIE 249 when developing test setups or regulatory criteria.

Keywords

Temporal light modulation; TLM; temporal light artefacts; TLAs; flicker; stroboscopic effect; phantom array; visibility predictors; frequency‑domain; time‑domain; solid‑state lighting; measurement; photometry; CIE 249:2022.

FAQ

Q: What is this standard?

A: CIE 249:2022 is a CIE Technical Report titled "Visual Aspects of Time‑Modulated Lighting Systems" that defines terminology, reviews visibility factors and presents methods to quantify and measure temporal light modulation and its visible effects. It is not a prescriptive limits standard but a guidance and measurement reference.

Q: What does it cover?

A: It covers perceptual effects caused by time‑varying luminous output from lighting systems (flicker, stroboscopic effects, phantom array), relevant influencing parameters (observer, stimulus, environment), two complementary measurement/quantification approaches (frequency‑ and time‑domain), example visibility predictors, and practical testing guidance. It excludes chromatic‑only modulation models, non‑visual effects, and capture/reproduction artefacts.

Q: Who typically uses it?

A: Lighting manufacturers, control‑gear designers, test laboratories, standards bodies, regulators, lighting designers and researchers use this report to align terminology, select measurement and analysis methods, and inform product testing, research and policy work on temporal aspects of lighting.

Q: Is it current or superseded?

A: CIE 249:2022 is current (active) as published in 2022 and remains the CIE technical report on visual aspects of time‑modulated lighting produced by TC 1‑83. It builds on earlier CIE TN 006:2016; users should check for any subsequent revisions or complementary CIE/ISO/IEC publications for updates.

Q: Is it part of a series?

A: It is an output of CIE Technical Committee TC 1‑83 on visual aspects of time‑modulated lighting systems and follows the earlier Technical Note TN 006:2016. It sits with other CIE publications on photometry, colour and lighting quality that together support measurement and application standards in lighting.

Q: What are the key keywords?

A: Temporal light modulation (TLM); temporal light artefacts (TLAs); flicker; stroboscopic effect; phantom array; visibility predictors; photometric measurement; solid‑state lighting; measurement guidance; CIE 249:2022.