ISO-10526-1999.pdf

Reference number ISO 10526:1999(E) CIE S 005-1998 © ISO 1999 INTERNATIONAL STANDARD ISO 10526 CIE S 005 Second edition 1999-06-01 CIE standard illuminants for colorimetry Illuminants colorimétriques normalisés CIE Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/19/2007 22:19:25 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 10526:1999(E) ©ISO 1999 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 the publisher. International Organization for Standardization Case postale 56 ? CH-1211 Genève 20 ? Switzerland Internetisoiso.ch Printed in Switzerland ii Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/19/2007 22:19:25 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 10526:1999(E) © ISO 1999 All rights reservediii 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. International Standard ISO 10526 was prepared as Standard CIE S 005 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 bodies 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. International Standard ISO 10526 was prepared by Technical Committee 2-33 (Rationalisation of CIE Standard Illuminants A and D65) of the CIE. Thissecondeditioncancelsandreplacesthefirstedition (ISO 10526:1991), of which it constitutes a technical revision. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/19/2007 22:19:25 MDTNo reproduction or networking permitted without license from IHS -,-,- Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/19/2007 22:19:25 MDTNo reproduction or networking permitted without license from IHS -,-,- CIE Central Bureau, Vienna S 005/E-1998 Kegelgasse 27, A-1030 Vienna, Austria UDC:535.65:006Descriptor:Standardisation of colour measurement 535.643.2Standard colorimetric system CIE S 005/E Standard CIE Standard Illuminants for Colorimetry Illuminants colorimétriques normalisés CIE CIE Normlichtarten für Farbmessung CIE Standards are copyrighted and shall not be reproduced in any form, entirely or partly, without the explicit agreement of the CIE. ISO 10526:1999(E) © ISO 1999 All rights reserved v Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/19/2007 22:19:25 MDTNo reproduction or networking permitted without license from IHS -,-,- CIE Standard Illuminants for Colorimetry II CIE S 005/E-1998 Foreword This CIE Standard has been prepared by CIE Technical Committee 2-33, “Rationalisation of CIE Standard Illuminants A and D65“*), and was approved by the CIE Board of Administration and the National Committees of the CIE. The numerical values of the relative spectral distributions of standard illuminants A and D65 defined by this Standard are the same, within an accuracy of six significant digits, as those defined in earlier versions of these illuminants. Standards produced by the CIE are concise documentation of data, defining aspects of light and lighting for which international harmony requires a unique definition. As such, CIE Standards are a primary source of internationally accepted and agreed data that can be taken, essentially unaltered, into universal standard systems. CIE Standard Illuminants for Colorimetry Contents 1.Scope1 2.Normative references1 3.Definitions2 4.CIE standard illuminant A3 4.1Definition3 4.2Theoretical basis4 4.3Supplementary notes4 5.CIE standard illuminant D655 5.1Definition5 5.2Experimental basis5 5.3Correlated colour temperature5 6.CIE standard sources for producing CIE standard illuminants5 6.1CIE source A5 6.2Source for CIE standard illuminant D656 7.Bibliography6 TABLE 1. Relative spectral power distribution of CIE standard illuminants A and D657 *) Chairman of this TC was K. D. Mielenz (US), members were: J. J. Hsia (US), J. R. Moore (GB), A. R. Robertson (CA), H. Terstiege (DE), J. F. Verrill (GB). CIE, 1998 ISO 10526:1999(E) vi © ISO 1999 All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/19/2007 22:19:25 MDTNo reproduction or networking permitted without license from IHS -,-,- CIE Standard Illuminants for Colorimetry CIE S 005/E-1998 1 1. Scope This International Standard specifies two illuminants for use in colorimetry. The illuminants, which are defined in clauses 4 and 5 of this International Standard, are as follows: a)CIE standard illuminant A This is intended to represent typical, domestic, tungsten-filament lighting. Its relative spectral power distribution is that of a Planckian radiator at a temperature of approximately 2 856 K. CIE standard illuminant A should be used in all applications of colorimetry involving the use of incandescent lighting, unless there are specific reasons for using a different illuminant. b)CIE standard illuminant D65 This is intended to represent average daylight and has a correlated colour temperature of approximately 6 500 K. CIE standard illuminant D65 should be used in all colorimetric calculations requiring representative daylight, unless there are specific reasons for using a different illuminant. Variations in the relative spectral power distribution of daylight are known to occur, particularly in the ultraviolet spectral region, as a function of season, time of day, and geographic location. However, CIE standard illuminant D65 should be used pending the availability of additional information on these variations. Values for the relative spectral power distribution of CIE standard illuminants A and D65 are given in Table 1 of this International Standard. Values are given at 1 nm intervals from 300 nm to 830 nm. The term “illuminant“ refers to a defined spectral power distribution, not necessarily realizable or provided by a source. Illuminants are used in colorimetry to compute the tristimulus values of reflected or transmitted object colours under specified conditions of illumination. The CIE has also defined illuminant C and other illuminants D. These illuminants are described in Publication CIE 15.2-1986 1, but they do not have the status of primary CIE standards accorded to the CIE standard illuminants A and D65 described in this International Standard. It is recommended that one of the two CIE standard illuminants defined in this International Standard be used wherever possible. This will greatly facilitate the comparison of published results. It is noted that in the fields of graphic arts and photography extensive use is also made of CIE illuminant D50, for example ISO 3644 2 and ISO 13655 3. In most practical applications of colorimetry, it is sufficient to use the values of CIE standard illuminants A and D65 at less frequent wavelength intervals or in a narrower spectral region than defined in this Standard. Data and guidelines that facilitate such practice are provided in Publication CIE 15.2 1, together with other recommended procedures for practical colorimetry. The term “source“ refers to a physical emitter of light, such as a lamp or the sky. In certain cases, the CIE recommends laboratory sources that approximate the spectral power distributions of CIE illuminants. In all cases, however, the definition of a CIE recommended source is secondary to the definition of the corresponding CIE illuminant, because of the possibility that, from time to time, new developments will lead to improved sources that represent a particular illuminant more accurately or are more suitable for laboratory use. Subclause 6.1 of this International Standard describes CIE source A, which is recommended for laboratory realizations of CIE standard illuminant A. At present, there is no CIE recommended source representing CIE standard illuminant D65. 2. Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this Standard are encouraged to investigate the possibility of applying most recent editions of the standards ISO 10526:1999(E) © ISO 1999 All rights reserved 1 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/19/2007 22:19:25 MDTNo reproduction or networking permitted without license from IHS -,-,- CIE Standard Illuminants for Colorimetry 2 CIE S 005/E-1998 indicated below. Members of CIE, the International Electrotechnical Commission (IEC) and the International Organization for Standardization (ISO) maintain registers of currently valid international standards. CIE 15.2-1986: Colorimetry CIE 17.4-1987: International Lighting Vocabulary - equivalent to IEC 50(845) CIE 51-1981: A method for assessing the quality of daylight simulators for colorimetry ISO/CIE 10527-1991: CIE standard colorimetric observers 3. Definitions For the purposes of this International Standard, the following definitions apply. These definitions are taken from Publication CIE 17.4-1987 4, where other relevant terms will also be found. 3.1 chromaticity co-ordinates Ratio of each of a set of three tristimulus values to their sum. NOTE1As the sum of the three chromaticity co-ordinates equals 1, two of them are sufficient to define a chromaticity. NOTE2In the CIE standard colorimetric systems, the chromaticity co-ordinates are represented by the symbols x, y, z and x10, y10, z10. 3.2 chromaticity diagram A plane diagram in which points specified by chromaticity co-ordinates represent the chromaticities of colour stimuli. 3.3 CIE standard illuminants The illuminants A and D65 defined by the CIE in terms of relative spectral power distributions. 3.4 CIE standard sources Artificial sources, specified by the CIE, whose relative spectral power distributions are approximately the same as those of CIE standard illuminants*. 3.5 CIE 1976 uniform-chromaticity-scale diagram; CIE 1976 UCS diagram The uniform-chromaticity-scale diagram produced by plotting in rectangular co- ordinates v against u, quantities defined by the equations u = 4X/(X + 15Y + 3Z) = 4x/(-2x + 12y + 3) v = 9Y/(X + 15Y + 3Z) = 9y/(-2x + 12y + 3) X, Y, Z are the tristimulus values in the CIE 1931 or 1964 standard colorimetric systems, and x, y are the corresponding chromaticity co-ordinates of the colour stimulus considered. 3.6 colour temperature Tc The temperature of a Planckian radiator whose radiation has the same chromaticity as that of a given stimulus. * This definition is a revision of the definition given in CIE 17.4-1987. ISO 10526:1999(E) 2 © ISO 1999 All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/19/2007 22:19:25 MDTNo reproduction or networking permitted without license from IHS -,-,- CIE Standard Illuminants for Colorimetry CIE S 005/E-1998 3 3.7 correlated colour temperature Tcp The temperature of the Planckian radiator whose perceived colour most closely resembles that of a given stimulus at the same brightness and under specified viewing conditions. NOTEThe recommended method of calculating the correlated colour temperature of a stimulus is to determine, on a chromaticity diagram, the temperature corresponding to the point on the Planckian locus that is intersected by the agreed isotemperature line containing the point representing the stimulus (see Publication CIE 15.2 1). 3.8 daylight illuminant Illuminant having the same, or nearly the same, relative spectral power distribution as a phase of daylight. 3.9 illuminant Radiation with a relative spectral power distribution defined over the wavelength range that influences object colour perception. 3.10 Planckian radiator; black-body Ideal thermal radiator that absorbs completely all incident radiation, whatever the wavelength, the direction of incidence or the polarization. This radiator has, for any wavelength and any direction, the maximum spectral concentration of radiance for a thermal radiator in thermal equilibrium at a given temperature. 3.11 Planckian locus The locus of points in a chromaticity diagram that represents chromaticities of the radiation of Planckian radiators at different temperatures. 3.12 primary light source Surface or object emitting light produced by a transformation of energy. 3.13 secondary light source Surface or object which is not self-emitting but receives light and re-directs it, at least in part, by reflection or transmission. 3.14 tristimulus values (of a colour stimulus) Amounts of the three reference colour stimuli, in a given trichromatic system, required to match the colour of the stimulus considered. NOTEIn the CIE standard colorimetric systems, the tristimulus values are represented by the symbols X, Y, Z and X10, Y10, Z10. 4. CIE standard illuminant A 4.1 Defi