1、BRITISH STANDARD BS 3900-D9: 1986 ISO 7724-2: 1984 Methods of Test for paints Part D9: Determination of colour and colour difference: measurement ISO title: Paints and varnishes Colorimetry Part 2: Colour measurement It is recommended that this Part be read in conjunction with the general informatio
2、n in the Introduction to BS 3900, issued separately. UDC 667.612:535.65BS3900-D9:1986 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 October1986 BS
3、I 07-1999 The Committees responsible for this British Standards are shown in BS3900:Introduction. The following BSI references relate to the work on this standard: Committee reference PVC/10 Draft for comment82/56106 DC ISBN 0 580 15364 9 Amendments issued since publication Amd. No. Date of issue Co
4、mmentsBS3900-D9:1986 BSI 07-1999 i Contents Page National foreword ii 0 Introduction 1 1 Scope and field of application 1 2 References 1 3 Principle 1 4 Choice of illumination and viewing conditions 1 5 Choice of standard colorimetric observer and standard illuminant 2 6 Apparatus 2 7 Sampling and p
5、reparation of test specimens 3 8 Reflectance standards 3 9 Procedure 4 10 Test report 6 11 Bibliography 6 Figure Powder press for preparing barium sulfate (BaSO 4 ) reflectance standards 5 Publications referred to Inside back coverBS3900-D9:1986 ii BSI 07-1999 National foreword This Part of BS3900 h
6、as been prepared under the direction of the Pigments, Paints and Varnishes Standards Committee. It is identical with ISO7724-2:1984 “Paints and Varnishes Colorimetry Part2: Colour measurement”, published by the International Organization for Standardization (ISO) with the active participation and ap
7、proval 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 terminology and certain conventions are not identical with those used in British Standards; attention is drawn
8、 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. In British Standards it is current practice to use the spelling “sulphur”, etc.,instead of “sulfur”, etc. Wherever the wor
9、ds “International Standard” and “part of ISO7724” appear, referring to this standard, they should be read as “British Standard” and “Part of BS3900” respectively, and where the identification “ISO7724-2” appears, it should be read as “BS3900-D9”. Cross-references International standard Corresponding
10、 British Standard BS3900 Methods of test for paints ISO1512:1974 Part A1:1970 Sampling (Technically equivalent) ISO1513:1980 Part A2:1983 Examination and preparation of samples for testing (Identical) ISO1514:1984 Part A3:1986 Standard panels for paint testing (Identical) ISO2808:1974 Part C5:1975 D
11、etermination of film thickness (Technically equivalent) ISO3534:1977 BS5532 Statistical terminology Part1:1984 Glossary of terms relating to probability and general terms relating to statistics (Identical) ISO5725:1981 BS5497 Precision of test methods Part1:1979 Guide for the determination of repeat
12、ability and reproducibility for a standard test method (Technically equivalent) BS3900 Method of test for paints ISO7724-1:1984 Part D8:1986 Determination of colour and colour difference: principles (Identical) ISO7724-3:1984 Part D10:1986 Determination of colour and colour difference: calculation (
13、Identical)BS3900-D9:1986 BSI 07-1999 iii The Technical Committee has reviewed the relevant provisions of the CIE publications to which reference is made in the text, and has decided that they are acceptable for use in conjunction with this standard. These publications are published by Commission Int
14、ernationale dclairage (CIE) and obtainable from the Hon. Librarian (National Illumination Committee), c/o Thorn Lighting Limited, Great Cambridge Road, Enfield, Middlesex EN11UL. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are
15、 responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi toiv, pages1 to6, an inside back cover and a back cover. This standard has b
16、een updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.iv blankBS3900-D9:1986 BSI 07-1999 1 0 Introduction This International Standard, ISO7724, comprises the following parts: Part 1: Principles; Part 2: Colo
17、ur measurement; Part 3: Calculation of colour differences. Parts 1, 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 between a te
18、st 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 changes
19、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 required for
20、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 method for determining the colour co-ordinates of paint films. The method is only applicable to paint films that
21、 appear to be uniformly of one colour, i.e.monochromatic, when examined with normal vision. Paint films that do not completely hide a non-transparent substrate represent an opaque system and may be measured by using the procedure described in this part of ISO7724. Luminescent paint films, transparen
22、t paint films and translucent paint films (for example for displays or lamp glass), retroreflecting paint films (for example for traffic signs), and metallic paint films are outside the scope of this part of ISO7724. 2 References ISO1512, Paints and varnishes Sampling. ISO1513, Paints and varnishes
23、Examination and preparation of samples for testing. ISO1514, Paints and varnishes Standard panels for testing. ISO2808, Paints and varnishes Determination of film thickness 1) . ISO3534, Statistics Vocabulary and symbols. ISO5725, Precision of test methods Determination of repeatability and reproduc
24、ibility by inter-laboratory tests. ISO7724-1, Paints and varnishes Colorimetry Part1: Principles. ISO7724-3, Paints and varnishes Colorimetry Part3: Calculation of colour differences. CIE Publication No. 15, Supplement NO. 1, Special metamerism index: change in illuminant. 3 Principle Measurement of
25、 the tristimulus values X 10 , Y 10 , Z 10by one of the following methods measurement of the spectral photometric characteristics (spectral reflectances or spectral reflectance factors) of the paint film with a spectrophotometer and calculation of the tristimulus values; measurement of the tristimul
26、us values with a tristimulus colorimeter. Calculation of the chromaticity co-ordinates x 10 , y 10or the colour co-ordinates in the approximately uniform CIE1976 (L*a*b*) colour space from the tristimulus values, as described in ISO7724-1. 4 Choice of illumination and viewing conditions One of the m
27、easuring conditions for illumination and viewing specified in ISO7724-1 should be chosen taking into account the surface texture, the reflection properties of the paint film tested and the information that is to be obtained by the measurement. 4.1 Smooth non-textured paint films All the measuring co
28、nditions specified in ISO7724-1 are suitable for determining the colour co-ordinates of smooth non-textured paint films. With high gloss specimens, results obtained under all measuring conditions are comparable if the tristimulus values determined with an integrating sphere without gloss trap are co
29、rrected for the surface reflection. NOTEThe surface reflection is the part of the light falling on a specimen that is reflected (diffusely and specularly) at the surface; another part is back-scattered by the pigments (volume reflection). The surface reflectance (Fresnel reflectance) for illuminatio
30、n at incidence between0 and8 on paint films is approximately 0,04. 1) At present at the stage of draft. (Revision of ISO 2808:1974.)BS3900-D9:1986 2 BSI 07-1999 For all other specimens the choice of measuring conditions depends on whether the specular reflection is to be included in or excluded from
31、 the measurement (see ISO7724-3). 4.1.1 Measurement including the specular reflection Use the measuring condition 8/d or d/8 (without gloss trap for both). NOTEIf the gloss changes without a visually perceptible change in colour, for example after weathering, the tristimulus values measured includin
32、g the specular reflection will generally not be influenced. 4.1.2 Measurement excluding the specular reflection Use the measuring condition 8/d or d/8 (with gloss trap for both) or45/0 or0/45. NOTEIf the gloss changes, the diffuse part of the surface reflection will change and consequently the trist
33、imulus values measured excluding the specular reflection change too. 4.2 Paint films with surface texture 4.2.1 Measurement including the specular reflection For the spectral characterization of the paint films with surface texture (for example textured finishes) use the measuring condition8/2 ord/8
34、 (without gloss trap for both). 4.2.2 Measurement excluding the specular reflection For matt or low gloss specimens use the measuring conditions8/d ord/8 (with gloss trap for both). Alternatively, use the measuring condition45/0 or 0/45 if the specimen is turned during the measurement, or the measur
35、ing condition45/0 if the specimen is illuminated toroidally or by two beams at90 to each other. NOTEFor paint films with surfaces that have high gloss and are textured, the measuring condition8/d or d/8 (with gloss trap) and45/0 or0/45 should not be used because random specularly reflected light may
36、 reach the detector. 5 Choice of standard colorimetric observer and standard illuminant The CIE1964 supplementary standard colorimetric observer and standard illuminant D65 should preferably be used. For the colorimetric determination of a special metamerism index (change in colour difference betwee
37、n two specimens caused by substituting a test illuminant for the reference illuminant, preferably D65 2) ) standard illuminant. A should be used as the test illuminant. Tristimulus colorimeters of early design are provided with filters that are only suitable for determining tristimulus values with t
38、he CIE1931 standard colorimetric system for standard illuminant C. If the colorimetric determination is based on the tristimulus method, the use of this combination of standard colorimetric observer and standard illuminant should be allowed, but its use should be reported. 6 Apparatus 6.1 Spectropho
39、tometer For high precision colorimetry, a single- or preferably a double-beam reflection spectrophotometer equipped with a prism or grating monochromator and a photometer head that satisfies the illumination and viewing conditions chosen as described in clause4 shall be used. Using these instruments
40、, the repeatability with which spectral reflectances or spectral reflectance factors can be measured should be better than the larger of the following two values:0,2 % of the reading or0,001 (absolute). The repeatability over long time intervals should not exceed these values by a factor of more tha
41、n3. NOTEFor the purpose of this part of ISO7724, the repeatability of the measuring method is the value below which the absolute difference between two single test results obtained for the same paint film under the same conditions (same operator, same spectrophotometer, at a short time interval) may
42、 be expected to lie with a95% probability. The repeatability is obtained by multiplying the standard deviation of the measuring method by the appropriate factor (seeISO5725). The accuracy should be better than the larger of the following two values: 0,5 % of the reading or0,002 (absolute). NOTEFor t
43、he purpose of this part of ISO7724, accuracy is the closeness of agreement between the true value and the mean result which would be obtained by applying the same method of colorimetry a very large number of times (see ISO3534). If the colorimetric measurements are for the objective supervision of c
44、olour reference standards clause0,d), a spectrophotometer of the type described above should be used in preference to theabridged type (6.2) or a tristimulus colorimeter(6.4). 2) see CIE Publication No. 15, Supplement No. 1.BS3900-D9:1986 BSI 07-1999 3 6.2 Abridged spectrophotometer For the applicat
45、ions described in clause 0, a) to c), an abridged spectrophotometer equipped with a photometer head that satisfies the illumination and viewing conditions chosen as described in clause4 is sufficient, except when highly chromatic paint films with steep spectral reflectance curves are to be measured.
46、 Such an instrument is a photometer containing at least16 interference filters distributed uniformly over the wavelength range400 to700nm and having a half-bandwidth of20nm or less. For the short- and long-term repeatability, the same conditions as those defined for spectrophotometers in6.1 apply. T
47、he accuracy should be better than the larger of the following two values: 1 % of the reading or0,004 (absolute). 6.3 Integrator For weighting the measured spectral photometric characteristics with the relative spectral power distribution of the standard illuminant S and the colour-matching functions
48、and the summation as described in ISO7724-1, a computer facility with adequate storage may be used. Abridged spectrophotometers and some automatic spectrophotometers embody electronic or mechanical integrators. 6.4 Tristimulus colorimeter The integration can also be performed optically with three tr
49、istimulus filters which shall be constituted so that the measurements appear in a simple linear relationship with the tristimulus values. Instruments of this category, which are termed tristimulus colorimeters, have to be equipped with a photometer head that satisfies the illumination and viewing conditions chosen as described in clause4. The three filters have to be fitted with respect to their spectral transmittance x(), y (), z() to the colour-matching functions, to the relative spectral power distribution of the sta
