ISO/CIE 23603:2024 PDF

Overview

ISO/CIE 23603:2024 - Standard method of assessing the spectral quality of daylight simulators for visual appraisal and measurement of colour - defines a standardized method to evaluate how well a daylight simulator reproduces the spectral irradiance of CIE standard daylight illuminants (e.g., D50, D55, D65, D75). The standard quantifies spectral fidelity for both the visible and ultraviolet (UV) ranges, prescribes a chromaticity tolerance, and assigns a quality grade (A–E) to simulators based on metamerism-based indices.

Key technical topics and requirements

• Chromaticity tolerance: The simulator’s chromaticity must not deviate by more than 0.015 in CIE 1976 u′v′ coordinates from the chromaticity of the target CIE daylight illuminant (per ISO/CIE 11664-5 and CIE 051.2-1999) for the simulator to be graded.
• Spectral assessment method: Uses spectroradiometry (see CIE 250:2022) to measure spectral irradiance and predefined computational procedures to evaluate spectral quality.
• Metamerism indices:
  • Visible-range metamerism index - quantifies mismatch in the visible wavelengths using pairs of virtual specimens that are metameric under the reference illuminant.
  • Ultraviolet-range metamerism index - quantifies mismatch due to fluorescence using virtual pairs that include fluorescent and non-fluorescent specimens specified by reflected radiance factor, fluorescence spectral distribution, and spectral external radiant efficiency.
• Computation steps: Normalization, chromaticity deviation calculation, generation of virtual metameric pairs, and computation of metamerism indices are described to yield objective, repeatable results.
• Quality grading: After meeting chromaticity tolerance and computing metamerism indices, the simulator receives a letter grade (A, B, C, D or E) separately for visible and UV performance, where A = highest quality.

Practical applications and users

ISO/CIE 23603:2024 is intended for organizations and professionals involved in colour-critical work:

• Colour laboratories and calibration facilities
• Manufacturers of daylight simulators and lighting equipment
• Quality control teams in textiles, paints, coatings, printing, plastics, automotive interiors, and consumer electronics
• Product designers and colour technologists conducting visual appraisal or instrumental colour measurement
• Standards bodies and testing laboratories performing conformance testing and supplier qualification

Using this standard helps ensure consistent, traceable colour appraisal and measurement under simulated daylight conditions and reduces metameric mismatches that can affect perception and measurement.

Related standards

• ISO/CIE 11664 series (Colorimetry - CIE standard observers and illuminants; Lab*, Luv*, u′v′ diagrams)
• CIE 051.2-1999 (method for assessing daylight simulators)
• CIE 250:2022 (spectroradiometric measurement of optical radiation sources)

Keywords: ISO/CIE 23603:2024, daylight simulator, spectral quality, chromaticity tolerance, metamerism index, colour measurement, visual appraisal, spectroradiometry.