SIST EN ISO 11664-1:2011
(Main)Colorimetry - Part 1: CIE standard colorimetric observers (ISO 11664-1:2007)
Colorimetry - Part 1: CIE standard colorimetric observers (ISO 11664-1:2007)
ISO 11664-1:2007 comprises ISO 10527:2007 and ISO 10527:2007/Cor.1:2008. Its technical content is identical to that of ISO 10527:2007. ISO 10527:2007/Cor.1:2008 changes the reference number of the standard from 10527 to 11664-1.
ISO 11664-1:2007 specifies colour-matching functions for use in colorimetry. Two sets of colour-matching functions are specified: colour-matching functions for the CIE 1931 standard colorimetric observer and colour-matching functions for the CIE 1964 standard colorimetric observer.
Farbmetrik - Teil 1: CIE farbmetrische Normalbeobachte (ISO 11664-1:2007)
Diese Internationale Norm legt Spektralwertfunktionen zur Anwendung in der Farbmetrik fest. Es werden zwei Sätze von Spektralwertfunktionen festgelegt.
a) Spektralwertfunktionen für den Normalbeobachter CIE 1931
Dieser Satz von Spektralwertfunktionen ist repräsentativ für die Farbabgleicheigenschaften von Beobachtern mit normalem Farbsehvermögen für Gesichtsfeldgrößen von etwa 1° bis etwa 4°, bei Adaption des Auges an photopisches Sehen (Tagessehen).
b) Spektralwertfunktionen für den Normalbeobachter CIE 1964
Dieser Satz von Spektralwertfunktionen ist repräsentativ für die Farbabgleicheigenschaften von Beobachtern mit normalem Farbsehvermögen für Gesichtsfeldgrößen über etwa 4°, bei Adaption des Auges an photopisches Sehen (Tagessehen) mit ausreichend hohem Niveau und mit einer solchen spektralen Strahlungsverteilung, das keine Beteiligung von Stäbchenrezeptoren der Netzhaut zu erwarten ist.
Colorimétrie - Partie 1: Observateurs CIE de référence pour la colorimétrie (ISO 11664-1:2007)
L'ISO 11664-1:2007 comprend l'ISO 10527:2007 et l'ISO 10527:2007/Cor.1:2008. Son contenu technique est identique � celui de l'ISO 10527:2007. L'ISO 10527:2007/Cor.1:2008 modifie le num�ro de r�f�rence de la norme de 10527 � 11664-1.
L'ISO 11664-1:2007 d�finit des fonctions colorim�triques pour leur emploi en colorim�trie. Deux ensembles de fonctions colorim�triques sont d�finis: les fonctions colorim�triques de l'observateur CIE 1931 de r�f�rence pour la colorim�trie et les fonctions colorim�triques de l'observateur CIE 1964 de r�f�rence pour la colorim�trie.
Kolorimetrija - 1. del: Normalno opazovanje kolorimetrije po CIE (ISO 11664-1:2007)
ISO 11664-1:2007 zajema ISO 10527:2007 in ISO 10527:2007/Cor.1:2008. Njegova tehnična vsebina je identična vsebini ISO 10527:2007. ISO 10527:2007/Cor.1:2008 spreminja referenčno številko standarda z 10527 na 11664-1.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 11664-1:2011
01-november-2011
Kolorimetrija - 1. del: Normalno opazovanje kolorimetrije po CIE (ISO 11664-
1:2007)
Colorimetry - Part 1: CIE standard colorimetric observers (ISO 11664-1:2007)
Farbmetrik - Teil 1: CIE farbmetrische Normalbeobachte (ISO 11664-1:2007)
Colorimétrie - Partie 1: Observateurs CIE de référence pour la colorimétrie (ISO 11664-
1:2007)
Ta slovenski standard je istoveten z: EN ISO 11664-1:2011
ICS:
17.180.20 Barve in merjenje svetlobe Colours and measurement of
light
SIST EN ISO 11664-1:2011 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 11664-1:2011
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SIST EN ISO 11664-1:2011
EUROPEAN STANDARD
EN ISO 11664-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2011
ICS 17.180.20
English Version
Colorimetry - Part 1: CIE standard colorimetric observers (ISO
11664-1:2007)
Colorimétrie - Partie 1: Observateurs CIE de référence pour Farbmetrik - Teil 1: CIE farbmetrische Normalbeobachte
la colorimétrie (ISO 11664-1:2007) (ISO 11664-1:2007)
This European Standard was approved by CEN on 17 March 2011.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same
status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2011 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 11664-1:2011: E
worldwide for CEN national Members.
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SIST EN ISO 11664-1:2011
EN ISO 11664-1:2011 (E)
Contents Page
Foreword .3
2
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SIST EN ISO 11664-1:2011
EN ISO 11664-1:2011 (E)
Foreword
The text of ISO 11664-1:2007 has been prepared by Technical Committee CIE “International Commission on
Illumination” of the International Organization for Standardization (ISO) and has been taken over as
EN ISO 11664-1:2011 by Technical Committee CEN/TC 139 “Paints and varnishes” the secretariat of which is
held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by October 2011, and conflicting national standards shall be withdrawn at
the latest by October 2011.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 11664-1:2007 has been approved by CEN as a EN ISO 11664-1:2011 without any
modification.
3
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SIST EN ISO 11664-1:2011
INTERNATIONAL ISO
STANDARD 11664-1
CIE S 014-1/E
First edition
2007-10-15
Corrected version
2008-11-01
Colorimetry —
Part 1:
CIE standard colorimetric observers
Colorimétrie —
Partie 1: Observateurs CIE de référence pour la colorimétrie
Reference number
ISO 11664-1:2007(E)
CIE S 014-1/E:2006
©
ISO 2007
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SIST EN ISO 11664-1:2011
ISO 11664-1:2007(E)
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© ISO 2007
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
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ii © ISO 2007 — All rights reserved
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SIST EN ISO 11664-1:2011
ISO 11664-1:2007(E)
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 ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
ISO 11664-1 was prepared as Standard CIE S 014-1/E by the International Commission on Illumination, which
has been recognized by the ISO Council as an international standardizing body. It was adopted by ISO under
a special procedure which requires approval by at least 75 % of the member bodes casting a vote, and is
published as a joint ISO/CIE edition.
The International Commission on Illumination (abbreviated as CIE from its French title) is an organization
devoted to international cooperation and exchange of information among its member countries on all matters
relating to the science and art of lighting.
ISO 11664-1 was prepared by CIE Division 2 Physical measurement of light and radiation.
ISO 11664-1 was initially published by ISO as ISO 10527:2007, and has subsequently been renumbered to be
part 1 of the ISO 11664 series.
ISO 11664 consists of the following parts, under the general title Colorimetry:
⎯ Part 1: CIE standard colorimetric observers [published previously as ISO 10527:2007, which has been
cancelled]
⎯ Part 2: CIE standard illuminants [published previously as ISO 10526:2007, which has been cancelled]
⎯ Part 4: CIE 1976 L*a*b* Colour space
© ISO 2007 — All rights reserved iii
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SIST EN ISO 11664-1:2011
ISO 11664-1:2007(E)
CIE S 014-1/E:2006
CIE S 014-1/E:2006
Standard
Colorimetry -
Part 1: CIE Standard Colorimetric
Observers
Colorimétrie - Partie 1: Observateurs de référence colorimétriques CIE
Farbmessung - Teil 1: CIE farbmetrische Normalbeobachter
CIE Standards are copyrighted and shall not be reproduced in any form, entirely or partly, without
the explicit agreement of the CIE.
CIE Central Bureau, Vienna CIE S 014-1/E:2006
Kegelgasse 27, A-1030 Vienna, Austria
UDC: 535.6.08 Descriptor: Colorimetry, reference data
© CIE 2006 — All rights reserved
© ISO 2007 — All rights reserved v
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SIST EN ISO 11664-1:2011
ISO 11664-1:2007(E)
CIE S 014-1/E:2006
© CIE, 2006
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means, electronic or mechanical, including photocopying and
microfilm, without permission in writing from CIE Central Bureau at the address below.
CIE Central Bureau
Kegelgasse 27
A-1030 Vienna
Austria
Tel.: +43 1 714 3187 0
Fax: +43 1 714 3187 18
e-mail: ciecb@ping.at
Web: www.cie.co.at/
© CIE 2006 — All rights reserved
vi © ISO 2007 — All rights reserved
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SIST EN ISO 11664-1:2011
ISO 11664-1:2007(E)
CIE S 014-1/E:2006
FOREWORD
Standards produced by the Commission Internationale de l’Eclairage (CIE) are a concise
documentation of data defining aspects of light and lighting, for which international harmony
requires such unique definition. CIE Standards are therefore a primary source of
internationally accepted and agreed data, which can be taken, essentially unaltered, into
universal standard systems.
This CIE Standard replaces ISO/CIE 10527:1991 and was approved by the CIE
Board of Administration and the National Committees of the CIE. This CIE Standard
has been prepared by CIE Division 2 "Physical measurement of light and radiation".
This standard contains only minor changes from the previous standard, in particular the
values in the tables of the colour matching functions and chromaticity coordinates of the CIE
1931 and 1964 standard colorimetric observers are identical with the previous standard, but it
has now been clarified that they apply for standard air.
TABLE OF CONTENTS
FOREWORD vii
INTRODUCTION 1
1. SCOPE 1
2. NORMATIVE REFERENCES 1
3. DEFINITIONS 1
4. SPECIFICATIONS 3
4.1 Colour-matching functions 3
4.2 Spectral chromaticity coordinates 3
5. DERIVATION OF THE COLOUR-MATCHING FUNCTIONS FOR THE CIE 1931
STANDARD COLORIMETRIC OBSERVER 3
5.1 Experimental basis 3
5.2 Transformation procedures 4
5.3 Transformation properties 4
5.4 Comparison with earlier data 4
6. DERIVATION OF THE COLOUR-MATCHING FUNCTIONS FOR THE CIE 1964
STANDARD COLORIMETRIC OBSERVER 5
6.1 Experimental basis 5
6.2 Transformation procedures 5
6.3 Transformation properties 5
6.4 Comparison with earlier data 5
7. PRACTICAL APPLICATION OF COLOUR-MATCHING FUNCTIONS FOR CIE
STANDARD COLORIMETRIC OBSERVERS 5
7.1 Obtaining tristimulus values 5
7.2 The basis for integration 6
7.3 Rod activity 6
7.4 The use of restricted data 6
7.5 Standard of reflectance 6
TABLE 1. COLOUR-MATCHING FUNCTIONS A ND CHROMATICITY COORDINATES
OF CIE 1931 STANDARD COLORIMETRIC OBSERVER 7
TABLE 2. COLOUR-MATCHING FUNCTIONS A ND CHROMATICITY COORDINATES
OF CIE 1964 STANDARD COLORIMETRIC OBSERVER 18
ANNEX: BIBLIOGRAPHY (INFORMATIVE) 29
© CIE, 2006
© CIE 2006 — All rights reserved
© ISO 2007 — All rights reserved vii
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SIST EN ISO 11664-1:2011
ISO 11664-1:2007(E)
CIE S 014-1/E:2006
COLORIMETRY - PART 1: CIE STANDARD COLORIMETRIC OBSERVERS
INTRODUCTION
Colours with different spectral compositions can look alike. An important function of
colorimetry is to determine whether a pair of such metameric colours will look alike. The use
of visual colorimeters for this purpose is handicapped by variations in the colour matches
made amongst observers classified as having normal colour vision. Visual colorimetry also
tends to be time-consuming. For these reasons, it has long been the practice in colorimetry to
make use of sets of colour-matching functions to calculate tristimulus values for colours:
equality of tristimulus values for a pair of colours indicates that the colour appearances of the
two colours match, when they are viewed in the same conditions by an observer for whom the
colour-matching functions apply. The use of standard sets of colour-matching functions
makes the comparison of tristimulus values obtained at different times and locations possible.
1. SCOPE
This International Standard specifies colour-matching functions for use in colorimetry. Two
sets of colour-matching functions are specified.
a) Colour-matching functions for the CIE 1931 standard colorimetric observer
This set of colour-matching functions is representative of the colour-matching properties of
observers with normal colour vision for visual field sizes of angular subtense from about 1° to
about 4°, for vision at photopic levels of adaptation.
b) Colour-matching functions for the CIE 1964 standard colorimetric observer
This set of colour-matching functions is representative of the colour-matching properties of
observers with normal colour vision for visual field sizes of angular subtense greater than
about 4°, for vision at sufficiently high photopic levels and with spectral power distributions
such that no participation of the rod receptors of the retina is to be expected.
2. NORMATIVE REFERENCES
The following referenced documents are indispensable for the application 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.
rd
CIE 15:2004. Colorimetry, 3 edition.
CIE 17.4-1987. International lighting vocabulary (ILV) - Joint publication IEC/CIE.
3. DEFINITIONS
For the purposes of this International Standard, the following definitions apply. These
definitions are taken from CIE 17.4-1987, where other relevant terms will also be found.
3.1 colour stimulus function, ϕ (λ) (see ILV 845-03-03)
λ
description of a colour stimulus by the spectral concentration of a radiometric quantity (such
as radiance or radiant power) as a function of wavelength
3.2 relative colour stimulus function, ϕ(λ) (see ILV 845-03-04)
relative spectral power distribution of the colour stimulus function
© CIE 2006 — All rights reserved
© ISO 2007 — All rights reserved 1
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3.3 metameric colour stimuli; metamers (see ILV 845-03-05)
spectrally different colour stimuli that have the same tristimulus values
3.4 monochromatic stimulus: spectral stimulus (see ILV 845-03-08)
stimulus consisting of a monochromatic radiation
3.5 equi-energy spectrum (see ILV 845-03-14)
spectrum of a radiation whose spectral concentration of a radiometric quantity as a function of
wavelength is constant throughout the visible region
3.6 additive mixture of colour stimuli (see ILV 845-03-15)
method of stimulation that combines on the retina the actions of various stimuli in such a
manner that they cannot be perceived individually
3.7 colour matching (see ILV 845-03-16)
action of making a colour stimulus appear the same in colour as a given colour stimulus
3.8 trichromatic system (see ILV 845-03-20)
system for specifying colour stimuli in terms of tristimulus values based on matching colours
by additive mixture of three suitably chosen reference colour stimuli
3.9 reference colour stimuli, [R], [G], [B]; [X], [Y], [Z]; [X ], [Y ], [Z ]; etc. (see ILV 845-03-
10 10 10
21)
set of three colour stimuli on which a trichromatic system is based
3.10 tristimulus values, R, G, B; X, Y, Z; X , Y , Z ; etc. (see ILV 845-03-22)
10 10 10
amounts of three reference colour stimuli, in a given trichromatic system, required to match
the colour of the stimulus considered
3.11 colour-matching functions, r(λ), g(λ), b(λ); x(λ), y(λ), z(λ) ; x (λ), y ()λ , z ()λ ; etc.
10 10 10
(see ILV 845-03-23)
tristimulus values of monochromatic stimuli of equal radiant power
3.12 CIE 1931 standard colorimetric system (X, Y, Z) (see ILV 845-03-28)
system for determining the tristimulus values of any spectral power distribution using the set
of reference colour stimuli [X], [Y], [Z], and the three CIE colour-matching functions
() () ()
xλ , yλ , zλ adopted by the CIE in 1931 and defined in this standard
3.13 CIE 1964 standard colorimetric system (X , Y , Z ) (see ILV 845-03-29)
10 10 10
system for determining the tristimulus values of any spectral power distribution using the set
of reference colour stimuli [X ], [Y ], [Z ], and the three CIE colour-matching functions
10 10 10
x ()λ , y ()λ , z ()λ adopted by the CIE in 1964 and defined in this standard
10 10 10
3.14 CIE colour-matching functions (see ILV 845-03-30)
functions x()λ , y()λ , z()λ in the CIE 1931 standard colorimetric system and
x ()λ , y ()λ , z ()λ in the CIE 1964 standard colorimetric system
10 10 10
3.15 CIE 1931 standard colorimetric observer (see ILV 845-03-31)
ideal observer whose colour-matching properties correspond to the CIE colour-matching
() () ()
functions xλ , yλ , zλ
3.16 CIE 1964 standard colorimetric observer (see ILV 845-03-32)
ideal observer whose colour-matching properties correspond to the CIE colour-matching
functions x ()λ , y (λ), z ()λ
10 10 10
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3.17 chromaticity coordinates, r, g, b; x, y, z; x , y , z ; etc. (see ILV 845-03-33)
10 10 10
ratio of each of a set of three tristimulus values to their sum
3.18 spectral chromaticity coordinates, r(λ), g(λ), b(λ); x(λ), y(λ), z(λ); x (λ), y (λ), z (λ); etc.
10 10 10
(see ILV 845-03-36)
chromaticity coordinates of monochromatic stimuli
3.19 spectral luminous efficiency, V(λ) (see ILV 845-01-22)
ratio of the radiant flux at wavelength λ to that at wavelength λ, such that both radiations
m
produce an equal visual response under specified photometric conditions and λ is chosen so
m
that the maximum value of this ratio is equal to 1
3.20 perfect reflecting diffuser (see ILV 845-04-54)
ideal isotropic diffuser with a reflectance equal to unity
4. SPECIFICATIONS
4.1 Colour-matching functions
The colour-matching functions x()λ , y(λ), z(λ) of the CIE 1931 standard colorimetric observer
are defined by the values given in Table 1, and those x (λ), y (λ), z (λ) of the CIE 1964
10 10 10
standard colorimetric observer are defined by the values given in Table 2. The values are
given at 1 nm wavelength intervals from 360 nm to 830 nm. If values are required at closer
wavelength intervals than 1 nm, they should be derived by linear interpolation.
4.2 Spectral chromaticity coordinates
Tables 1 and 2 also give values for the spectral chromaticity coordinates, x(λ), y(λ), z(λ);
x (λ), y (λ), z (λ); these have been derived from the appropriate colour-matching functions
10 10 10
by forming the ratios:
x()λ y(λ) z()λ
x()λ = , y()λ = and z()λ =
x()λ + y()λ + z()λ x()λ + y()λ + z()λ x()λ + y()λ + z()λ
x ()λ y (λ)
10 10
x ()λ = , y ()λ = and
10 10
x ()λ + y ()λ + z ()λ x ()λ + y ()λ + z ()λ
10 10 10 10 10 10
z ()λ
10
z ()λ =
10
x ()λ + y ()λ + z ()λ
10 10 10
Note: All wavelengths are for standard air.
5. DERIVATION OF THE COLOUR-MATCHING FUNCTIONS FOR THE CIE 1931
STANDARD COLORIMETRIC OBSERVER
5.1 Experimental basis
The CIE 1931 colour-matching functions, x(λ), y(λ), z(λ) were derived from experimental
work carried out by Wright (1928-1930) and by Guild (1931) in which a total of 17 observers
matched the monochromatic stimuli of the spectrum, over the range of about 400 nm to
700 nm, with additive mixtures of red, green and blue lights, using observing fields of 2°
angular subtense.
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5.2 Transformation procedures
The experimental results were converted into those that would have been obtained if the
matching had been carried out using, as reference colour stimuli, monochromatic radiations
of wavelengths 700 nm for the red [R], 546,1 nm for the green [G] and 435,8 nm for the blue
[B], measured in units such that equal quantities of [R], [G] and [B] were required to match the
equi-energy spectrum.
The results for the 17 observers were averaged and then slightly adjusted so that by
adding together suitable proportions of the [R], [G], [B] colour-matching functions
r()λ , g()λ , b()λ it was possible to obtain a function identical to that of the CIE spectral
luminous efficiency, V(λ); the proportions used were in the ratios of 1,000 0 to 4,590 7 to
0,060 1, and these were then the relative luminances of unit quantities of [R], [G] and [B]. The
CIE 1931 colour-matching functions were then determined by the following equations:
x()λ = [0,49r()λ + 0,31g()λ + 0,20b(λ)]n
y()λ = [0,176 97r(λ)+ 0,812 40g()λ + 0,010 63b(λ)]n
z()λ = [0,00r()λ + 0,01g()λ + 0,99b(λ)]n
where n is a normalising constant given by
V()λ
n=
0,176 97r()λ + 0,812 40g()λ + 0,010 63b()λ
n is a constant, not a function of wavelength, because the coefficients 0,176 97, 0,812 40,
and 0,010 63 are in the same ratios to one another as the ratio of 1,000 0 to 4,590 7 to
0,060 1; n is equal to
1,000 0 + 4,590 7 + 0,060 1
= 5,650 8
0, 176 97 + 0,812 40 + 0,010 63
The values of x()λ , y()λ , z()λ given in Table 1 from 360 nm to 400 nm and from
700 nm to 830 nm are extrapolations.
5.3 Transformation properties
The transformation given in the above equations was chosen to achieve the following
objectives. First, the y()λ function is identical to the V(λ) function. Second, the values of
x()λ , y()λ , z()λ are all positive for all wavelengths of the spectrum (unlike r()λ , g()λ , b()λ one
of which is negative at most wavelengths because of the need to desaturate spectral stimuli
when matching them with red, green, and blue reference stimuli). Third, the values of z()λ
are zero for wavelengths longer than 650 nm. Fourth, the values of x(λ) are nearly zero at
( ) ( )
wavelengths around 505 nm. Fifth, the values of xλ and yλ are small at the short-
wavelength end of the spectrum. Sixth, the equi-energy spectrum is specified by equal
amounts of X, Y and Z.
Because the y()λ function is identical to the V(λ) function, the Y tristimulus value is
proportional to luminance.
5.4 Comparison with earlier data
The values of x()λ , y()λ , z()λ given in Table 1 for the spectral range of 380 nm to 780 nm at
5 nm intervals, when rounded to four decimal places, agree closely with those originally
published in 1931. There are only three minor differences: at λ = 775 nm the new value of
x()λ is 0,000 1 instead of 0,000 0; at λ = 555 nm, y(λ) = 1,000 0 instead of 1,000 2 and at
λ = 740 nm, y()λ = 0,000 2 instead of 0,000 3. These changes are considered insignificant in
most colorimetric computations.
When the relative luminances of unit quantities of [R], [G] and [B] are deduced from the
data of Tabie 1, the values obtained are 1,000 0 to 4,588 8 to 0,060 3 instead of 1,000 0 to
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CIE S 014-1/E:2006
4,590 7 to 0,060 1, the relative radiances being 71,893 8 to 1,374 7 to 1,000 0 instead of
72,096 2 to 1,379 1 to 1,000 0. These changes are also considered insignificant in practice.
The values given in CIE 15:2004 at 5 nm intervals agree exactly with those given in
Table 1.
6. DERIVATION OF THE COLOUR-MATCHING FUNCTIONS FOR THE CIE 1964
STANDARD COLORIMETRIC OBSERVER
6.1 Experimental basis
The CIE 1964 colour-matching functions x (λ), y (λ), z (λ) were derived from experimental
10 10 10
work carried out by Stiles and Burch (1959) and by Speranskaya (1959) in which a total of 67
observers matched monochromatic stimuli of the spectrum from approximately 390 nm to
830 nm with additive mixtures of red, green, and blue lights, using observing fields of 10°
angular subtense (but ignoring the central 4° or so).
6.2 Transformation procedures
The experimental results were converted into those that would have been obtained if the
matching had been carried out using, as reference colour stimuli, monochromatic radiations
-1 -1
of wavenumbers 15 500 cm for the red [R ], 19 000 cm for the green [G ], and
10 10
-1
22 500 cm for the blue [B ], corresponding approximately to wavelengths 645,2 nm,
10
526,3 nm and 444,4 nm, respectively. The units used for the quantities of [R ], [G ] and [B ]
10 10 10
were such that equal amounts were required to match the equi-energy spectrum. A weighted
average of the results for the 67 observers was used to provide a set of colour-matching
functions r ()ν , g (ν), b ()ν . The CIE 1964 colour-matching functions were then derived by
10 10 10
the following equations:
() () ( ) ( )
x ν = 0,341080r ν + 0,189 145g ν + 0,387 529b ν
10 10 10 10
y ()ν = 0,139 058r ()ν + 0,837 460g (ν)+ 0,073 316b (ν)
10 10 10 10
z ()ν = 0,000 000r ()ν + 0,039 553g (ν)+ 2,026 200b (ν)
10 10 10 10
In Table 2, the CIE 1964 colour-matching functions x (λ), y (λ), z ()λ are given on a
10 10 10
wavelength basis and were obtained by interpolation from the frequency-based functions
given above. The values in the range of 360 nm to 390 nm are extrapolations.
6.3 Transformation properties
The transformation given in the equations in 6.2 was chosen to achieve a colorimetric system
(X , Y , Z ) having a coordinate system broadly similar to that of the CIE 1931 (X, Y, Z)
10 10 10
system. However, in the 1964 system, the data were not constrained to fit the CIE V(λ)
spectral luminous efficiency function, and the Y tristimulus value is not proportional to
10
luminance calculated using the V(λ) function.
6.4 Comparison with earlier data
The values given in CIE 15:2004 at 5 nm intervals agree exactly with those given in Table 2.
7. PRACTICAL APPLICATION OF COLOUR-MATCHING FUNCTIONS FOR CIE
STANDARD COLORIMETRIC OBSERVERS
7.1 Obtaining tristimulus values
The data given in Tables 1 and 2 provide the tristimulus values and chromaticity coordinates
of all monochromatic stimuli directly or by interpolation. For stimuli consisting of radiation of
© CIE 2006 — All rights reserved
© ISO 2007 — All rights reserved 5
---------------------- Page: 19 ----------------------
SIST EN ISO 11664-1:2011
ISO 11664-1:2007(E)
CIE S 014-1/E:2006
various wavelengths, the tristimulus values X, Y, Z and X , Y , Z are calculated by
10 10 10
integration over the spectral range 360 nm to 830 nm using the following equations:
Xk= ϕλλx dλ Xk= ϕλλx dλ
()() ( ) ( )
λ 10 10 λ 10
∫ ∫
λ λ
Yk= ϕλyλ dλ Yk= ϕλλy dλ
() ( ) ( ) ( )
λ 10 10 λ 10
∫ ∫
λ λ
Zk= ϕλλz dλ Zk= ϕλλz dλ
() ( ) ( ) ( )
λ 10 10 λ 10
∫ ∫
λ λ
where
ϕ()λ is the colour stimulus function of the stimulus considered;
λ
x()λ , y()λ , z()λ , x (λ), y ()λ , z ()λ are the appropriate CIE colour-matching functions;
10 10 10
k and k are constants.
10
Tristimulus values are usually evaluated on a relative basis, and the constants, k and
k are then chosen according to agreed conventions; however, it is essential that, for stimuli
10
that will be considered together, the same value for k (or for k ) be adopted, so that all the
10
tristimulus values involved are assessed on the same basis. For reflecting object-colours, k
and k shall be chosen so that Y and Y are equal to 100 for the perfect reflecting diffuser,
10 10
and, for transmitting object-colours, so that Y and Y are equal to 100 for the perfect
10
transmitter. In the case of primary light sources, if it is required that Y be equal to the absolute
value of the photometric quantity, k shall be equal to K , the maximum spectral luminous
m
efficacy (which is equal to 683 Im/W) and ϕ (λ) shall then be the spectral concentration of
λ
the radiometric quantity corresponding to the photometric quantity required.
7.2 The basis for integration
The integration step in the equations in 7.1 implies additivity of colour matches: that is, if two
colour stimuli [C1] and [C2] have tristimulus values X Y , Z , and X , Y , Z , respectively, then
1 1 1 2 2 2
the additive mixture of [C1] and [C2] will have tristimulus values X + X , Y + Y , Z + Z .
1 2 1 2 1 2
Experimental investigations have shown that, although additivity of this type sometimes fails
to occur, the principle of additivity is sufficiently valid for predicting colour matches
...
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