ISO/CIE 23603:2024
(Main)Standard method of assessing the spectral quality of daylight simulators for visual appraisal and measurement of colour
Standard method of assessing the spectral quality of daylight simulators for visual appraisal and measurement of colour
This document specifies a method of assessing the spectral quality of the irradiance provided by a daylight simulator to be used for visual appraisal of colours or for colour measurements and a method of assigning a quality grade to the simulator. It specifies the maximum permissible deviation of the chromaticity of the simulator from the chromaticity of the CIE standard daylight illuminant or CIE daylight illuminant being simulated for a daylight simulator to be graded by this method.
Méthode normalisée d'évaluation de la qualité spectrale des simulateurs de lumière du jour pour le jugement visuel et la mesure des couleurs
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Standards Content (Sample)
International
Standard
ISO/CIE 23603
First edition
Standard method of assessing
2024-10
the spectral quality of daylight
simulators for visual appraisal and
measurement of colour
Méthode normalisée d'évaluation de la qualité spectrale des
simulateurs de lumière du jour pour le jugement visuel et la
mesure des couleurs
Reference number
© ISO/CIE 2024
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© ISO/CIE 2024 – All rights reserved
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Requirements . 4
4.1 Chromaticity tolerance .4
4.2 Quality grade .4
5 Test methods . 4
5.1 Spectroradiometry .4
5.2 Computations .5
5.2.1 Normalization .5
5.2.2 Chromaticity deviation .5
5.2.3 Virtual metameric pairs .5
5.2.4 Computing metamerism indices .5
6 Tables . 7
Bibliography . 19
© ISO/CIE 2024 – All rights reserved
iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
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This document was prepared by the International Commission on Illumination (CIE) in cooperation with
Technical Committee ISO/TC 274, Light and lighting.
This first edition of ISO/CIE 23603 cancels and replaces ISO 23603:2005, which has been technically revised.
The main changes are as follows:
— prior reference numbers of the document (CIE S 012:2004, ISO 23603:2005) replaced by ISO/CIE 23603;
— normative references updated;
— terms and definitions updated;
— minor editorial changes.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
© ISO/CIE 2024 – All rights reserved
iv
Introduction
The purpose of the assessment method described in this document is to quantify the suitability of the
spectral irradiance distribution of a practical daylight simulator of CIE daylight illuminant D55, D75 or
CIE standard daylight illuminants D50 and D65 for the visual appraisal and measurement of colours of
fluorescent or non-fluorescent specimens.
The basis for the assessment is the special metamerism index for change in illuminant, using pairs of virtual
(rather than real) specimens specified by their reflecting and fluorescing properties. The pairs of specimens
are metameric matches under the CIE daylight illuminant, when evaluated with the CIE 1964 standard
colorimetric observer. The method described in this document quantifies the mismatch when the pairs of
virtual specimens are illuminated by the daylight simulator under test and evaluated by the same standard
colorimetric observer.
A visible range metamerism index is derived to quantify the suitability of the simulator for the visible
wavelength range.
An ultraviolet range metamerism index is derived using a different set of virtual metameric pairs, each pair
having a fluorescent and a non-fluorescent specimen which spectrally match for the CIE daylight illuminant
and CIE standard colorimetric observer. The non-fluorescent specimen in each pair is specified by its spectral
radiance factor. The fluorescent specimen in each pair is specified by its spectral reflected radiance factor,
relative spectral distribution of radiance due to fluorescence and spectral external radiant efficiency of the
fluorescent specimen. The ultraviolet range metamerism index quantifies the mismatch due to fluorescence
that results from the use of the daylight simulator and the CIE 1964 standard colorimetric observer.
© ISO/CIE 2024 – All rights reserved
v
International Standard ISO/CIE 23603:2024(en)
Standard method of assessing the spectral quality of daylight
simulators for visual appraisal and measurement of colour
1 Scope
This document specifies a method of assessing the spectral quality of the irradiance provided by a daylight
simulator to be used for visual appraisal of colours or for colour measurements and a method of assigning
a quality grade to the simulator. It specifies the maximum permissible deviation of the chromaticity of the
simulator from the chromaticity of the CIE standard daylight illuminant or CIE daylight illuminant being
simulated for a daylight simulator to be graded by this method.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO/CIE 11664-1, Colorimetry — Part 1: CIE standard colorimetric observers
ISO/CIE 11664-2, Colorimetry — Part 2: CIE standard illuminants
ISO/CIE 11664-4, Colorimetry — Part 4: CIE 1976 L*a*b* colour space
ISO/CIE 11664-5, Colorimetry — Part 5: CIE 1976 L*u*v* Colour Space and u′, v′ Uniform Chromaticity Scale Diagram
CIE 051.2-1999, A Method for Assessing the Quality of Daylight Simulators for Colorimetry
CIE 250:2022, Spectroradiometric measurement of optical radiation sources
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
CIE maintains a terminology database for use in standardization at the following address:
— CIE e-ILV: available at https:// cie .co .at/ e -ilv
3.1
daylight simulator
device for the visual appraisal or measurement of the colour of materials or surfaces that provides spectral
irradiance approximating a CIE standard illuminant representing a phase of daylight
[SOURCE: CIE S 017:2020, Entry 17-23-025]
© ISO/CIE 2024 – All rights reserved
3.2
quality grade
class of quality of simulation of the spectral irradiance of a CIE illuminant by a
simulator, expressed as a letter symbol A, B, C, D or E, with class A representing the highest quality
[SOURCE: CIE S 017:2020, Entry 17-23-024]
3.3
reflectance factor
R
quotient of the flux reflected in the directions delimited by a given cone with apex at a surface element,
Φ , and the flux reflected in the same directions by a perfect reflecting diffuser identically irradiated or
n
illuminated, Φ
d
Φ
n
R=
Φ
d
Note 1 to entry: The definition holds for a surface element, for the part of the reflected radiation contained in a given
cone with apex at the surface element, and for incident radiation of given spectral composition, polarization and
geometric distribution.
Note 2 to entry: The reflectance factor is also defined spectrally and is called spectral reflectance factor, R(λ).
Note 3 to entry: The ideal isotropic (Lambertian) diffuser with reflectance or transmittance equal to 1 is called a
perfect diffuser.
Note 4 to entry: For regularly reflecting surfaces that are irradiated or illuminated by a beam of small solid angle, the
reflectance factor can be much larger than 1 if the cone includes the mirror image of the source.
Note 5 to entry: If the solid angle of the cone approaches 2π sr, the reflectance factor approaches the reflectance for
the same conditions of irradiation.
Note 6 to entry: If the solid angle of the cone approaches 0 sr, the reflectance factor approaches the radiance factor or
luminance factor for the same conditions of irradiation.
Note 7 to entry: The reflectance factor has unit one.
[SOURCE: CIE S 017:2020, Entry 17-24-070, modified — Notes 8 and 9 to entry omitted.]
3.4
radiance factor
β
e
quotient of the radiance of a surface element in a specified direction, L and the radiance of the perfect
e,n
reflecting diffuser or perfect transmitting diffuser identically irradiated and viewed, L
e,d
L
e,n
β =
e
L
e,d
Note 1 to entry: The definition holds for a surface element of a non-self-radiating medium, in a specified direction and
under specified conditions of irradiation.
Note 2 to entry: Radiance factor is equivalent to reflectance factor or luminance factor when the cone angle is infinitely
small, and is equivalent to reflectance when the cone angle is 2π sr. These quantities are also defined spectrally and
called spectral radiance factor, β(λ), and spectral reflectance factor, R(λ).
Note 3 to entry: The ideal isotropic (Lambertian) diffuser w
...
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