CIE-130-1998.pdf
ISBN 3 900 734 88 7 COMMISSION INTERNATIONALE DE LÉCLAIRAGE INTERNATIONAL COMMISSION ON ILLUMINATION INTERNATIONALE BELEUCHTUNGSKOMMISSION PRACTICAL METHODS FOR THE MEASUREMENT OF REFLECTANCE AND TRANSMITTANCE CIE 130 - 1998 UDC: 535.345.1 Descriptor: Regular transmittance 535.312 Regular reflectance 535.361 .i Diffuse transmittance 535.361.2 Diffuse reflectance CIE 130 - 1998 This Technical Report has been prepared by CIE Technical Committee 2-14 of Division 2 “Physical measurement of light and radiation” and has been approved by the Board of Administration of the Commission Internationale de IEclairage for study and application. The document reports on current knowledge and experience within the specific field of light and lighting described, and is intended to be used by the CIE membership and other interested parties. It should be noted, however, that the status of this document is advisory and not mandatory. The latest CIE proceedings or CIE NEWS should be consulted regarding possible subsequent amendments. Ce rapport technique a été préparé par le Comité Technique CIE 2-14 de la Division 2 Mesures physiques de la lumière et des radiations et a été approuvé par le Bureau dAdministration de la Commission Internationale de IEclairage, pour étude et application. Le document traite des connaissances courantes et de lexpérience dans le domaine spécifique indiqué de la lumière et de léclairage, et il est établi pour lusage des membres de la CIE et autres groupements intéressés. II faut cependant noter que ce document est indicatif et non obligatoire. Pour connaître déventuels amendements, consulter les plus récents comptes rendus de la CIE ou le CIE NEWS. Dieser Technische Bericht ist vom CIE Technischen Komitee 2-14 der Division 2 Physikalische Messungen von Licht und Strahlung” ausgearbeitet und vom Vorstand der Commission Internationale de IEclairage gebilligt worden. Das Dokument berichtet über den derzeitigen Stand des Wissens und Erfahrung in dem behandelten Gebiet von Licht und Beleuchtung; es ist zur Verwendung durch CIE-Mitglieder und durch andere Interessierte bestimmt. Es sollte jedoch beachtet werden, daß das Dokument eine Empfehlung und keine Vorschrift ist. Die neuesten CIE-Tagungsberichte oder das CIE NEWS sollten im Hinblick auf mögliche spätere Änderungen zu Rate gezogen werden. Any mention of organisations or products does not imply endorsement by the CIE. Whilst every care has been taken in the compilation of any lists, up to the time of going to press, these may not be comprehensive. Toute mention dorganisme ou de produit nimplique pas une préférence de la CIE. Malgré le soin apporté à la compilation de tous les documents jusquà la mise sous presse, ce travail ne saurait être exhaustif. Die Erwähnung von Organisationen oder Erzeugnissen bedeutet keine Billigung durch die CIE. Obgleich große Sorgfalt bei der Erstellung von Verzeichnissen bis zum Zeitpunkt der Drucklegung angewendet wurde, ist es möglich, daß diese nicht vollständig sind. O CIE 1998 II COPYRIGHT International Commission on Illumination Licensed by Information Handling Services COPYRIGHT International Commission on Illumination Licensed by Information Handling Services CIE I30 - 1998 Ohis guide is dedicated to the memety of the late Profesmr Jiirgen Iírochmann. The following members of TC 2-1 4 “Measurement of Reflectance and Transmittance, including Turbid Media” took part in the preparation of this Technical Report. The TC comes under CIE Division 2 “Physical Measurement of Light and Radiation”. J. Krochmann* (Chairman) P. Polato (Chairman) F. Geotti-Bianchini D. Gundlach J.J. Hsia L. Morren H. Terstiege J. Verrill Germany Italy Italy Germany U.S.A. Belgium Germany Great Britain * Professor J. Krochmann passed away on 27 January 1991. III COPYRIGHT International Commission on Illumination Licensed by Information Handling Services COPYRIGHT International Commission on Illumination Licensed by Information Handling Services STD-CIE 130-ENGL 1998 900bLY5 0005770 SOT CIE 130 . 1998 Table of Contents Summary vi1 Résumé v11 Zusammenfassung VIII 1 . Scope 1 2 . Definitions 1 2.1 Processes 1 2.1.1 Reflection . 1 2.1.2 Transmission . 1 2.1.3 Absorption . 2 2.1.4 Regular reflection; specular reflection (Regular transmission; direct transmission) . 2 2.1.6 Mixed reflection (Mixed transmission) 2 2.1.5 Diffuse reflection (Diffuse transmission) . 2 2.1.7 Isotropic diffuse reflection (Isotropic diffuse transmission) 2 2.1.8 Perfect reflecting diffuser (Perfect transmitting diffuser) . 2 2.1.9 Translucent medium 2 2.2 Characteristics . 2 2.2.1 Reflectance ) (Transmittance ( 2 ) ) 2 2.2.2 Regular reflectance ur) (Regular transmittance (q) 2 2.2.3 Diffuse reflectance (pd) (Diffuse transmittance (a) 2 2.2.4 Radiance factor/Luminance factor (Bi 3 2.2.5 Radiance/Luminance coefficient (4) . 3 2.2.6 Absorptance (a) . 3 3 . Parameters affecting the characterictics 3 3.1.1 Spectral composition of the incident radiation 3 3.2 Geometric conditions 4 3.3 Thin and thick translucent samples . 6 3.4 Other parameters . 7 4 . Measurement principles . 7 4.1 Absolute and relative methods 7 4.2 Spectral and integral characteristics . 7 4.2.1 Spectral method . 7 4.2.2 Integral method 7 4.2.3 Photometer, radiometer, spectroradiometer . 8 4.3 Spatial evaluation . 8 4.3.1 Gonioradiometers/goniophotometers . 8 4.3.2 Practical methods 8 4.3.2.1 Methods using an integrating sphere 8 4.3.2.2 Directional methods 8 5 . Measuring equipment 9 5.1 Components . 9 5.2 Equipment for irradiation 9 5.2.1 Single and double beam . 9 5.2.2 Geometric conditions . 10 5.2.3 Spectral conditions . 10 5.2.4 Polarization 1 0 5.2.5 Lamps 11 5.3 Equipment for detection 11 5.3.1 Irradiance/illuminance and radiance/luminance measurement 11 5.3.2 Radiometer/photometer head . 11 5.3.3 Radiometer/photometer . 12 5.4 Monochromator 12 3.1 Spectral parameters . 3 3.1.2 Integral characteristics . 4 5.3.4 Data recording . 12 IV COPYRIGHT International Commission on Illumination Licensed by Information Handling Services COPYRIGHT International Commission on Illumination Licensed by Information Handling Services . - . STD-CIE 130-ENGL 1998 900bLY5 0005971i 84b = CIE 130 . 1998 6 . Integrating sphere 13 6.1 Measurment principles . 13 6.2 Sphere theory . 13 6.3 Substitution and comparison methods 14 6.5 Sphere geometry 15 6.5.1 Diameters of the sphere and sample port . 15 6.5.2 Ports 16 6.5.3 Radiometer/photometer head . 18 6.5.3.1 Irradiance/illuminance measurement 18 6.5.3.2 Radiance/luminance measurement . 19 6.5.4 Auxiliary lamp/auxiliary screen . 19 6.5.5 Additional observations on sphere geometry 20 7 . Measurement of reflection characteristics using a sphere radiometerlphotometer 21 7.1 Reflectance for directionally incident radiation 21 7.1.1 Introduction 21 7.1.2 Equipment for irradiation 21 7.1.3 Sphere geometry . 21 7.1.3.1 Thin samples 21 7.1.3.1.1 Near-normal incidence 21 7.1.3.1.2 Other angles of incidence 22 7.1.3.2 Thick translucent samples 22 7.1.3.2.1 Near normal incidence 22 7.1.3.2.2 Other angles of incidence 22 7.1.4 Reflectance standards . 23 7.1.5 Measurements and calculations . 24 7.1 S.1 Thin samples 24 7.1 S.2 Thick translucent samples 24 7.1.6 Corrections in the case of mixed reflection . 25 7.2 Diffuse reflectance 26 7.2.1 Samples with diffuse reflection only 26 7.2.2 Samples with mixed reflection 26 6.4 Sphere coating . 14 7.2.3 Diffuse reflectance standards . 26 7.2.4 Measurements and calculations . 27 7.2.4.1 Thin samples 27 7.2.4.2 Thick translucent samples 28 7.3 Reflectance for hemispherical irradiation 28 7.3.1 Surface reflecting materials 28 7.3.1.1 Integrating sphere method 28 7.3.1.3 Measurements and calculations 30 7.3.2 Thick translucent samples 30 7.3.2.1 Principle . 30 7.3.2.2 Measurements and calculations 30 7.3.1.2 Diffuse reflectance standards . 30 8 . Measurement of transmission characteristics using a sphere radiometer/photometer 31 8.1 Transmittance for directionally incident radiation 31 8.1.1 Absolute methods 31 8.1.2.1 Sphere with small sample port 31 8.1.2.2 Sphere with large sample port 32 8.1.2.3 Measurement of transmittance as a function of the angle of incidence . 33 8.1.4.1 Small sample pori . 34 8.1.2 Integrating sphere method . 31 8.1.3 Transmittance standards 33 8.1.4 Measurements and calculations . 34 8.1.4.2 Large sample port . 34 8.1.5 Corrections in the case of mixed transmission . 35 COPYRIGHT International Commission on Illumination Licensed by Information Handling Services COPYRIGHT International Commission on Illumination Licensed by Information Handling Services . . - STDOCIE L30-ENGL 1778 900bL45 0005772 782 CIE 130 . 1998 8.2 Diffuse transmittance 37 8.2.2 Samples with mixed transmission 37 8.2.3 Measurements and calculations . 37 8.3 Transmittance for hemispherical irradiation 38 8.3.1 Equipment for irradiation 38 8.3.2 Integrating sphere method . 39 8.3.3 Measurements and calculations . 39 8.3.4 Calculation of .5;i from measured values of z ( E ) 40 9.1 Samples with regular reflectance only . 41 9.1.1 Integrating sphere method . 41 9.1.2 Illuminance ratio method 41 9.1.2.1 Absolute method . 41 9.1.2.1.1 9.1.2.1.2 Goniometric method 42 9.1.2.2 Relative method 43 9.2 Samples with mixed reflection 45 9.2.1 Luminance ratio method . 45 9.2.1.1 Relative method 45 9.2.1.2 Goniometric method . 45 9.2.2 Integrating sphere method . 45 10.1 Samples with regular transmittance only . 46 10.1.1 Integrating sphere method . 46 10.1.2 Illuminance ratio method 46 10.2 Samples with mixed transmittance 47 10.2.1 Luminance ratio method . 47 10.2.2 Integrating sphere method . 48 11 . Measurement of absorptance . 48 11.1 4n method 48 11.2 Calculation from reflectance and transmittance . 49 12 . Measurement of radiance/luminance factor and radiance/luminance coefficient . 49 12.1 Radiance/luminance factor . 49 12.1.1 Measurement geometry . 49 12.1.2 Measurement with directional irradiation and observation 50 12.1.3 Measurement with diffuse irradiation and normal observation 51 12.1.4 Standards for radiance/luminance factor 52 12.2 Radiance/luminance coefficient 52 13 . Sources of error and corrections 52 13.1 General 52 13.2 Absolute and relative methods 52 13.3 Integral or spectral determinations 53 13.3.1 Possible sources of error in detectors 53 13.3.2 Possible additional sources of error with integral detectors . 53 13.3.3 Possible additional sources of error with spectroradiometers . 54 13.4 Geometrical considerations 54 13.4.1 Methods using an integrating sphere . 54 13.4.2 Methods without an integrating sphere . 55 8.2.1 Samples with diffuse transmission only 37 9 . Measurement of regular reflectance . 41 Method with double reflection (V-W method) . 41 1 O . Measurement of regular transmittance . 46 14 . Characterization of the measuring equipment 55 14.1 Measurable quantities and required reference materials . 55 14.2 Equipment for irradiation 56 14.3 Monochromator 56 14.4 Integrating sphere . 56 14.5 Detector 56 14.6 Further information . 56 15 . Bibliography . 57 VI COPYRIGHT International Commission on Illumination Licensed by Information Handling Services COPYRIGHT International Commission on Illumination Licensed by Information Handling Services STDmCIE 130-ENGL 1776 = 900b145 0005973 bL9 m CIE 130 - 1998 PRACTICAL METHODS FOR THE MEASUREMENT OF REFLECTANCE AND TRANSMITTANCE SUMMARY The characteristics of materials related to their reflection and transmission properties are defined in accordance with the International Lighting Vocabulary and other relevant CIE publications. The parameters affecting these characteristics and the principles of measurement involved, which are the same whether the measurement is made in terms of spectral or weighted (e.g. luminous) characteristics, are specified. Methods, using an integrating sphere, are recommended for the measurement of - reflectance for directional p, p() and hemispherical pdf incidence of radiation, - diffuse reflectance pd, - transmittance for directional 2 , Z(E) and hemispherical c j l incidence of radiation, - diffuse transmittance cj. Specific methods are also recommended for the measurement of - regular reflectance pI - regular transmittance 2;, - radiancdluminance factor ß (radiance/luminance coefficient 9). The absorptance acan either be measured directly or calculated from the measured values of reflectance and transmittance. Both procedures are described. The principal measurement errors are examined and, where possible, methods for their elimination indicated. METHODES PRATIQUES DE MESURE DES FACTEURS DE REFLEXION ET DE TRANSMISSION RESUME Les caractéristiques des matériaux qui se réfèrent à leurs propriétés de réflexion et de transmission des rayonnements optiques sont définies en conformité avec le Vocabulaire International de I'Eclairage et autres publications de la CIE sur le même sujet. Les paramètres pouvant affecter les caractéristiques susdites et les principes de mesure sont spécifiés, ces principes étant les mêmes qu'il s'agisse de mesures de caractéristiques spectrales ou intégrales (lumineuses par exemple). Des méthodes de mesure faisant usage d'une sphère intégratrice sont recommandées pour les déterminations - du facteur de réflexion sous incidence directionnelle p, p( - Radiometric and Photometric Characteristics of Materials and their Measurement 2; - Absolute Methods for Reflection Measurements 3; - A Review of Publications on Properties and Reflection Values of Material Reflection The reflection and transmission properties of materials in the wavelength range of optical radiation, particularly light, are important in many fields. This report deals mainly with the wavelength range 200 nm .e A 800 nm. 5.3.3 RADIOM ETE WPHOTOM ETER In addition to the items mentioned in 5.3.2, the accuracy of a radiometer/photometer may also be affected by the following: - linearity error; - error of the display unit; - fatigue; - temperature dependence; - errors arising from range changes; -warm-up period; - influence of supply voltage. A numerical assessment of the above properties is described in Publication CIE 69 16. Additional properties affecting the accuracy of the radiometer/photometer, for which a numerical assessment cannot yet be recommended are: - ageing effects; - zero setting drift; - mechanical durability; - climatic durability; - effects of external magnetic fields. 5.3.4 DATA RECORDING Direct recording of data with a small computer/microprocessor in combination with a printer/plotter is recommended. This is essential for spectral measurements where many data points must be recorded and corrected. 5.4 Monochromator Instruments designed to measure spectral characteristics generally incorporate a monochromator 17. This may use a prism or a diffraction grating as the dispersive element. Alternativeiy a filter monochromator using an interference filter or wedge may be used. Some instruments use double monochromator
