1、BRITISH STANDARD BS3900-D8: 1986 ISO7724-1: 1984 Colour Principles Methods of test for paints Part D8: Determination of colour and colour difference: principles ISO title: Paints and varnishes Colorimetry Part1: Principles It is recommended that this Part be read in conjunction with the general info
2、rmation in the Introduction to BS3900, issued separately. UDC 667.612:535.65BS3900-D8:1986 This British Standard, having been prepared under the directionof the Pigments, Paintsand Varnishes StandardsCommittee, was published under the authority ofthe Board of BSI and comes intoeffect on 31 October19
3、86 BSI 06-1999 The Committees responsible for this British Standard are shown inBS3900: Introduction. The following BSI references relate to the work on this standard: Committee reference PVC/10 Draft for comment82/56105 DC ISBN 0 580 15365 7 Amendments issued since publication Amd. No. Date of issu
4、e CommentsBS3900-D8:1986 BSI 06-1999 i Contents Page National foreword ii 0 Introduction 1 1 Scope and field of application 1 2 References 1 3 Colour co-ordinates 1 4 Standard illuminants 3 5 Spectral radiometric characteristics 5 Table 1 Colour-matching functions for the10 observer at5nm wavelength
5、 intervals 4 Table 2 10 tristimulus values for the perfect reflecting diffuser for standard illuminants D65 and A 5 Table 3 Relative spectral power distribution S ,of standard illuminants D65 and A at5nm wavelength intervals 6 Table 4 Spectral radiometric characteristics for colorimetry of paint fil
6、ms 7 Publications referred to Inside back coverBS3900-D8:1986 ii BSI 06-1999 National foreword This Part of BS3900 has been prepared under the direction of the Pigments, Paints and Varnishes Standards Committee. It is identical with ISO7724/1-1984 “Paints and varnishes Colorimetry Part1: Principles”
7、, published by the International Organization for Standardization (ISO) with the active participation and approval of the United Kingdom. Terminology and conventions. The text of the international standard has been approved as suitable for publication as a British Standard without deviation. Some te
8、rminology and certain conventions are not identical with those used in British Standards; attention is drawn especially to the following. The comma has been used as a decimal marker. In British Standards it is current practice to use a full point on the baseline as the decimal marker. Wherever the w
9、ords “International Standard” and “part of ISO7724” appear, referring to this standard, they should be read as “British Standard” and “Part of BS3900” respectively. The Technical Committee has reviewed the relevant provisions of the CIEpublications to which reference is made in the text, and has dec
10、ided that they are acceptable for use in conjunction with this standard. These publications are published by Commission Internationale dclairage (CIE) and obtainable from the Hon. Librarian (National Illumination Committee), c/o Thorn Lighting Limited, Great Cambridge Road, Enfield, Middlesex EN11UL
11、. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-references International standard
12、 Corresponding British Standard BS3900 Methods of test for paints ISO2813-1978 Part D5:1980 Measurement of specular gloss of non-metallic paint films at20,60 and85 (Identical) ISO3668-1976 Part D1:1978 Visual comparison of the colour of paints (Identical) ISO7724/2-1984 Part D9:1986 Determination of
13、 colour and colour difference: measurement (Identical) ISO7724/3-1984 Part D10:1986 Determination of colour and colour difference: calculation (Identical) Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to8, an inside back cover and a back cover. T
14、his standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS3900-D8:1986 BSI 06-1999 1 0 Introduction This International Standard, ISO7724, comprises the following parts: Part 1: Principles; Pa
15、rt 2: Colour measurement; Part 3: Calculation of colour differences. Parts1,2 and3 of ISO7724 describe methods for the instrumental determination of the colour co-ordinates and colour differences of paint films, as required for such purposes as a) the objective description of colour differences betw
16、een a test specimen (a test panel coated with a paint, or a specimen from a painted article) and a reference specimen; b) determining colour deviations in the production of painted articles so that the results may be used for the control or regulation of the process; c) the objective description of
17、changes in colour caused by weathering and other chemical or physical influences; d) the objective supervision of colour reference standards. NOTEColour reference standards are subject to ageing, which may lead in the course of time to pronounced changes in colour. High accuracy colorimetry is requi
18、red for the timely detection of these changes. This is of particular importance when ordering against such reference standards. 1 Scope and field of application This part of ISO7724 describes the colorimetric terms and fundamental requirements necessary for determining the colour co-ordinates of pai
19、nt films and related materials. 2 References ISO2813, Paints and varnishes Measurement of specular gloss of non-metallic paint films at20, 60and85. ISO3668, Paints and varnishes Visual comparison of the colour of paints. ISO7724/2, Paints and varnishes Colorimetry Part2: Colour measurement. ISO7724/
20、3, Paints and varnishes Colorimetry Part3: Calculation of colour differences. CIE Publication No.15, Colorimetry, Official CIE Recommendations. CIE Publication No.15, Supplement No.2, Recommendations on uniform color spaces Color difference equations Psychometric color terms. CIE Publication No.38,
21、Radiometric and photometric characteristics of materials and their measurement. 3 Colour co-ordinates A colour is uniquely characterized for a defined observer and a defined light source by the co-ordinates of a point in a space formed by three mutually perpendicular vectors. From among the various
22、colour co-ordinates recommended by the Commission Internationale de lclairage (CIE), the colour co-ordinates given in3.1 and3.2 are specified for colorimetric measurements on paint films in accordance with this International Standard. 3.1 Colour co-ordinates in the CIE1964 supplementary standard col
23、orimetric system The colour co-ordinates in this system (see CIE Publication No. 15) are the tristimulus value Y 10and the chromaticity co-ordinates x 10and y 10 .BS3900-D8:1986 2 BSI 06-1999 The chromaticity co-ordinates are formed by the tristimulus values where () denotes the colour stimulus func
24、tion, which is the product of the relative spectral power distribution S for the standard illuminant (see clause4) and the spectral function that characterizes the reflectance of the paint film (see clause5); 10 (), 10 () and 10 (2) are the colour-matching functions (see note1) used to define the CI
25、E1964standard colorimetric observer for observation fields of angular subtense larger than4 (10 observer) (see Table 1); l and u are the respective summation limits for the short-wave and long-wave limits of the visible spectrum; % is the width of the wavelength interval (for the choice of l and u,
26、and%, see ISO7724/2); k 10is a normalizing factor calculated by using the equation which causes the tristimulus value Y 10for the perfect reflecting diffuser to assume a value of100. In this system, the colour co-ordinates do not provide a perceptually uniform colour space (see3.2). NOTE 1The coeffi
27、cients 10 (2), 10 (2) and 10 (2) were formerly termed CIE spectral tristimulus values or CIE trichromatic weighting coefficients. NOTE 2Colour co-ordinates in the CIE1931 standard colorimetric system are defined by analogous equations using the colour-matching functions (), () and () of the CIE1931
28、standard colorimetric observer for the2 observation field. Colour-matching functions at5nm wavelength intervals are given in CIE Publication No.15. The10 observation field corresponds more closely with practice than the2 observation field and is consistent with the viewing conditions recommended in
29、ISO3668 for the visual comparison of the colour of paints. 3.2 Colour co-ordinates in the CIE1976 (L * a * b * ) colour space In comparison with the CIE1964 colorimetric system (see3.1), the colour co-ordinates in the perceptually more uniform CIE1976 (L * a * b * ) colour space (see CIE Publication
30、 No.15 Supplement No.2) are specified for the evaluation of colour differences. x y z x y z x y zBS3900-D8:1986 BSI 06-1999 3 The colour co-ordinates are calculated from the following equations: X n , Y n , Z nare the10 tristimulus values of the perfect reflecting diffuser under the chosen standard
31、illuminant (see Table 2). NOTEIf2 tristimulus values are used, L * ,a * ,b *co-ordinates for the2 observer will be obtained. The corresponding values for X nandZ ncan be calculated from the2 chromaticity co-ordinates for the standard illuminants D65 and A (see CIE Publication No.15) with Y n =100. I
32、t is sometimes convenient to express colour not in terms of the rectangular co-ordinates L * ,a * ,b * , but in terms of the rectilinear lightness and the polar co-ordinates chroma and hue (see CIE Publication No.15 Supplement No.2). These may be calculated from L * ,a * ,b *to give 4 Standard illum
33、inants The CIE standard illuminant D65 which corresponds to natural daylight at a correlated colour temperature of about6500K (see CIE Publication No.15), should be specified for colour measurements in accordance with this International Standard. NOTEThe standard illuminant C corresponds to natural
34、daylight at a correlated colour temperature of6744K. Its spectral distribution does not approach that of natural daylight so closely as that of standard illuminant D65, especially in the ultraviolet region. The standard illuminant A, which represents the light of a tungsten lamp and corresponds in i
35、ts spectral distribution to a perfect black body at a temperature of2856K, should be specified for the colorimetric determination of a special metamerism index (see clause5 of ISO7724/2). Numerical values for the relative spectral power distribution S of standard illuminants D65 and A are given in T
36、able 3. L * = 116 (Y/Y n ) 1/3 16 for Y/Y n 0,008 856 L * = 903,3 (Y/Y n ) for Y/Y n 0,008 856 f(X/X n ) = 7,787 (X/X n )+16/116 for X/X n 0,008 856 f(Y/Y n ) = 7,787 (Y/Y n )+16/116 for Y/Y n 0,008 856 f(Z/Z n ) = 7,787(Z/Z n )+16/116 for Z/Z n 0,008 856 X, Y, Z denote the10 tristimulus values of t
37、he paint film; CIE1976 psychometric lightness L * CIE1976 a b chroma C * ab =(a *2 + b *2 ) 1/2 CIE1976 a b hue angle h ab =arctan (b * /a * ) between0 and360BS3900-D8:1986 4 BSI 06-1999 Table 1 Colour-matching functions for the10 observer at5nm wavelength intervals nm 10 () 10 () 10 () nm 10 () 10
38、() 10 () 380 385 390 395 400 405 410 415 420 425 430 435 440 445 450 455 460 465 470 475 480 485 490 495 500 505 510 515 520 525 530 535 540 545 550 555 560 565 0,0002 0,0007 0,0024 0,0072 0,0191 0,0434 0,0847 0,1406 0,2045 0,2647 0,3147 0,3577 0,3837 0,3867 0,3707 0,3430 0,3023 0,2541 0,1956 0,1323
39、 0,0805 0,0411 0,0162 0,0051 0,0038 0,0154 0,0375 0,0714 0,1177 0,1730 0,2365 0,3042 0,3768 0,4516 0,5298 0,6161 0,7052 0,7938 0,0000 0,0001 0,0003 0,0008 0,0020 0,0045 0,0088 0,0145 0,0214 0,0295 0,0387 0,0496 0,0621 0,0747 0,0895 0,1063 0,1282 0,1528 0,1852 0,2199 0,2536 0,2977 0,3391 0,3954 0,460
40、8 0,5314 0,6067 0,6857 0,7618 0,8233 0,8752 0,9238 0,9620 0,9822 0,9918 0,9991 0,9973 0,9824 0,0007 0,0029 0,0105 0,0323 0,0860 0,1971 0,3894 0,6568 0,9725 1,2825 1,5535 1,7985 1,9673 2,0273 1,9948 1,9007 1,7454 1,5549 1,3176 1,0302 0,7721 0,5701 0,4153 0,3024 0,2185 0,1592 0,1120 0,0822 0,0607 0,04
41、31 0,0305 0,0206 0,0137 0,0079 0,0040 0,0011 0,0000 0,0000 600 605 610 615 620 625 630 635 640 645 650 655 660 665 670 675 680 685 690 695 700 705 710 715 720 725 730 735 740 745 750 755 760 765 770 775 780 1,1240 1,0891 1,0305 0,9507 0,8563 0,7549 0,6475 0,5351 0,4316 0,3437 0,2683 0,2043 0,1526 0,
42、1122 0,0813 0,0579 0,0409 0,0286 0,0199 0,0138 0,0096 0,0066 0,0046 0,0031 0,0022 0,0015 0,0010 0,0007 0,0005 0,0004 0,0003 0,0002 0,0001 0,0001 0,0001 0,0000 0,0000 0,6583 0,5939 0,5280 0,4618 0,3981 0,3396 0,2835 0,2283 0,1798 0,1402 0,1076 0,0812 0,0603 0,0441 0,0318 0,0226 0,0159 0,0111 0,0077 0
43、,0054 0,0037 0,0026 0,0018 0,0012 0,0008 0,0006 0,0004 0,0003 0,0002 0,0001 0,0001 0,0001 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000
44、0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 570 0,8787 0,9556 0,0000 575 580 585 590 595 0,9512 1,0142 1,0743 1,1185 1,1343 0,9152 0,8689 0,8256 0,7774 0,7204 0,0000 0,0000 0,0000 0,0000 0,0000 x y z x y zBS3900-D8:1986 BSI 06-1999 5 Table 2 10 tristimulus val
45、ues for the perfect reflecting diffuser for standard illuminants D65 and A 5 Spectral radiometric characteristics 5.1 General Of the various possible spectral radiometric characteristics that describe the reflecting properties of materials (see CIE Publication No.38), the three characteristics defin
46、ed in5.1.1 to5.1.3 are used in this part of ISO7724 for paint film colorimetry. 5.1.1 spectral reflectance factor R (): The ratio of the radiant flux reflected in the directions within a given cone to that reflected in the same directions by a perfect reflecting diffuser identically irradiated in th
47、e observed wavelength interval. NOTEIn contrast to the recommendations of the CIE (see CIE Publication No.15), this part of ISO7724 specifies the spectral reflectance factor instead of the spectral radiance factor. The instruments commercially available are not suitable for accurate measurement of t
48、he spectral radiance factor because of systematic errors caused by the divergence of the reflected light beams. 5.1.2 spectral reflectance A(): The ratio of the reflected radiant flux to the incident flux in the observed wavelength interval. 5.1.3 spectral diffuse reflectance A (d) (): The ratio of
49、the reflected radiant flux to the incident flux in the observed wavelength interval measured with the specularly reflected light (gloss) excluded. 5.2 Illumination and viewing conditions The various modes for measuring the reflected radiation to be specified for colour measurements in accordance with this International Standard are listed in Table 4. In the directional illumination and viewing beams the angle between the beam axis and any ray shall not exceed5. The diffuse il
