欢迎来到麦多课文档分享! | 帮助中心 海量文档,免费浏览,给你所需,享你所想!
麦多课文档分享
全部分类
  • 标准规范>
  • 教学课件>
  • 考试资料>
  • 办公文档>
  • 学术论文>
  • 行业资料>
  • 易语言源码>
  • ImageVerifierCode 换一换
    首页 麦多课文档分享 > 资源分类 > PDF文档下载
    分享到微信 分享到微博 分享到QQ空间

    ASTM D2244-2007e1 Standard Practice for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color Coordinates.pdf

    • 资源ID:511282       资源大小:164.19KB        全文页数:10页
    • 资源格式: PDF        下载积分:10000积分
    快捷下载 游客一键下载
    账号登录下载
    微信登录下载
    二维码
    微信扫一扫登录
    下载资源需要10000积分(如需开发票,请勿充值!)
    邮箱/手机:
    温馨提示:
    如需开发票,请勿充值!快捷下载时,用户名和密码都是您填写的邮箱或者手机号,方便查询和重复下载(系统自动生成)。
    如需开发票,请勿充值!如填写123,账号就是123,密码也是123。
    支付方式: 支付宝扫码支付    微信扫码支付   
    验证码:   换一换

    加入VIP,交流精品资源
     
    账号:
    密码:
    验证码:   换一换
      忘记密码?
        
    友情提示
    2、PDF文件下载后,可能会被浏览器默认打开,此种情况可以点击浏览器菜单,保存网页到桌面,就可以正常下载了。
    3、本站不支持迅雷下载,请使用电脑自带的IE浏览器,或者360浏览器、谷歌浏览器下载即可。
    4、本站资源下载后的文档和图纸-无水印,预览文档经过压缩,下载后原文更清晰。
    5、试题试卷类文档,如果标题没有明确说明有答案则都视为没有答案,请知晓。

    ASTM D2244-2007e1 Standard Practice for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color Coordinates.pdf

    1、Designation: D 2244 071Standard Practice forCalculation of Color Tolerances and Color Differences fromInstrumentally Measured Color Coordinates1This standard is issued under the fixed designation D 2244; the number immediately following the designation indicates the year oforiginal adoption or, in t

    2、he case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1NOTEEquation 28

    3、 was corrected editorially in November 2008.INTRODUCTIONThis practice originally resulted from the consolidation of a number of separately publishedmethods for the instrumental evaluation of color differences.As revised in 1979, it included four colorspaces in which color-scale values could be measu

    4、red by instruments, many of which were obsolete,and the color differences calculated by ten equations for different color scales. The sections onapparatus, calibration standards and methods, and measurement procedures served little purpose in thelight of modern color-measurement technology. The revi

    5、sion published in 1993 omitted these sections,and limited the color spaces and color-difference equations considered, to the three most widely usedin the paint and related coatings industry.Aprevious revision added two new color tolerance equationsand put two of the color difference equations from t

    6、he 1993 version in an informative appendix forhistorical purposes.1. Scope*1.1 This practice covers the calculation, from instrumentallymeasured color coordinates based on daylight illumination, ofcolor tolerances and small color differences between opaquespecimens such as painted panels, plastic pl

    7、aques, or textileswatches. Where it is suspected that the specimens may bemetameric, that is, possess different spectral curves thoughvisually alike in color, Practice D 4086 should be used to verifyinstrumental results. The tolerances and differences determinedby these procedures are expressed in t

    8、erms of approximatelyuniform visual color perception in CIE 1976 CIELABopponent-color space (1)2, CMC tolerance units (2), CIE94tolerance units (3), the DIN99 color difference formula givenin DIN 6176 (4), or the new CIEDE2000 color difference units(5).1.2 For product specification, the purchaser an

    9、d the sellershall agree upon the permissible color tolerance between testspecimen and reference and the procedure for calculating thecolor tolerance. Each material and condition of use may requirespecific color tolerances because other appearance factors, (forexample, specimen proximity, gloss, and

    10、texture), may affectthe correlation between the magnitude of a measured colordifference and its commercial acceptability.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-p

    11、riate safety and health practices and determine the applica-bility of regulatory requirements prior to use.2. Referenced Documents2.1 ASTM Standards:3D 1729 Practice for Visual Appraisal of Colors and ColorDifferences of Diffusely-Illuminated Opaque MaterialsD 4086 Practice for Visual Evaluation of

    12、MetamerismE 284 Terminology of AppearanceE 308 Practice for Computing the Colors of Objects byUsing the CIE SystemE 805 Practice for Identification of Instrumental Methods ofColor or Color-Difference Measurement of MaterialsE 1164 Practice for Obtaining Spectrometric Data forObject-Color Evaluation2

    13、.2 Other Standards:1This practice is under the jurisdiction of ASTM Committee E12 on Color andAppearance and is the direct responsibility of Subcommittee E12.04 on Color andAppearance Analysis.Current edition approved May 1, 2007. Published May 2007. Originallyapproved in 1964. Last previous edition

    14、 approved in 2005 as D 2244 05.2The boldface numbers in parentheses refer to the list of references at the end ofthis standard.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information

    15、, refer to the standards Document Summary page onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.DIN 6176 Farbmetrische, Bestimmung von Farbabstndenbe

    16、i Krperfarben nach der DIN99-Formel43. Terminology3.1 Terms and definitions in Terminology E 284 are appli-cable to this practice.3.2 Definitions of Terms Specific to This Standard:3.2.1 colorimetric spectrometer, nspectrometer, one com-ponent of which is a dispersive element (such as a prism,gratin

    17、g or interference filter or wedge or tunable or discreteseries of monochromatic sources), that is normally capable ofproducing as output colorimetric data (such as tristimulusvalues and derived color coordinates or indices of appearanceattributes). Additionally, the colorimetric spectrometer mayalso

    18、 be able to report the underlying spectral data from whichthe colorimetric data were derived.3.2.1.1 DiscussionAt one time, UV-VIS analytical spec-trophotometers were used for colorimetric measurements. To-day, while instruments intended for use in color measurementsshare many common components, UV-

    19、VIS analytical spectro-photometers are designed to optimize their use in chemometricquantitative analysis, which requires very precise spectralposition and very narrow bandpass and moderate baselinestability. Colorimetric spectrometers are designed to optimizetheir use as digital simulations of the

    20、visual colorimeter or asthe source of spectral and colorimetric information forcomputer-assisted color matching systems. Digital colorimetryallows more tolerance on the spectral scale and spectralbandwidth but demand much more stability in the radiometricscale.3.2.2 color tolerance equation, na math

    21、ematical expres-sion, derived from acceptability judgments, which distorts themetric of color space based on the coordinates in that colorspace, of a reference color, for the purpose of single numbershade passing.3.2.2.1 DiscussionThe color tolerance equation computesa pass/fail value based on which

    22、 of the pair of specimens isassigned the designation “standard.” Thus, inter-changing thereference and test specimens will result in a change in thepredicted level of acceptance between the specimens while theperceived difference is unchanged. A color difference equationquantifies distance in a colo

    23、r space using the metric of thatspace. Inter-changing the reference and test specimens does notchange either the perceived or predicted color differences.4. Summary of Practice4.1 The differences in color between a reference and a testspecimen are determined from measurements made by use of aspectra

    24、l based or filter based colorimeter. Reflectance readingsfrom spectral instruments are converted by computations tocolor-scale values in accordance with Practice E 308, or thesecolor-scale values may be read directly from instruments thatautomatically make the computations. Color-difference unitsare

    25、 computed, from these color-scale values, and approximatethe perceived color differences between the reference and thetest specimen.5. Significance and Use5.1 The original CIE color scales based on tristimulusvalues X, Y, Z and chromaticity coordinates x, y are not uniformvisually. Each subsequent c

    26、olor scale based on CIE values hashad weighting factors applied to provide some degree ofuniformity so that color differences in various regions of colorspace will be more nearly comparable. On the other hand, colordifferences obtained for the same specimens evaluated indifferent color-scale systems

    27、 are not likely to be identical. Toavoid confusion, color differences among specimens or theassociated tolerances should be compared only when they areobtained for the same color-scale system. There is no simplefactor that can be used to convert accurately color differencesor color tolerances in one

    28、 system to difference or toleranceunits in another system for all colors of specimens.5.2 For uniformity of practice, the CIE recommended in1976 the use of two color metrics. The CIELAB metric, withits associated color-difference equation, has found wide accep-tance in the coatings, plastics, textil

    29、es and related industries.While the CIELAB equation has not completely replaced theuse of Hunter LH,aH,bH, this older scale is no longerrecommended for other than legacy users, and is thereforeincluded in an Appendix for historical purposes. The CIELABcolor-difference equation is also not recommende

    30、d in thispractice for use in describing small and moderate colordifferences (differences with magnitude less than 5.0 D E*abunits). The four more recently defined equations, documentedhere, are highly recommended for use with color-differences inthe range of 0.0 to 5.0 DE*abunits.5.3 Users of color

    31、tolerance equations have found that, ineach system, summation of three, vector color-differencecomponents into a single scalar value is very useful fordetermining whether a specimen color is within a specifiedtolerance from a standard. However, for control of color inproduction, it may be necessary

    32、to know not only the magni-tude of the departure from standard but also the direction ofthis departure. It is possible to include information on thedirection of a small color difference by listing the threeinstrumentally determined components of the color difference.5.4 Selection of color tolerances

    33、 based on instrumentalvalues should be carefully correlated with a visual appraisal ofthe acceptability of differences in hue, lightness, and saturationobtained by using Practice D 1729. The three tolerance equa-tions given here have been tested extensively against such datafor textiles and plastics

    34、 and have been shown to agree with thevisual evaluations to within the experimental uncertainty of thevisual judgments. That implies that the equations themselvesmisclassify a color difference with a frequency no greater thanthat of the most experienced visual color matcher.5.5 While color differenc

    35、e equations and color toleranceequations are routinely applied to a wide range of illuminants,they have been derived or optimized, or both, for use underdaylight illumination. Good correlation with the visual judg-ments may not be obtained when the calculations are madewith other illuminants. Use of

    36、 a tolerance equation for otherthan daylight conditions will require visual confirmation of thelevel of metamerism in accordance with Practice D 4086.4Available from Beuth Verlag GmbH, 10772 Berlin, Germany.D224407126. Description of Color-Difference and Color-ToleranceEquations6.1 CIE 1931 and 1964

    37、 Color SpacesThe daylight colorsof opaque specimens are represented by points in a spaceformed by three rectangular axes representing the lightnessscale Y and chromaticity scales x and y, where:x 5XX 1 Y 1 Z(1)y 5YX 1 Y 1 Z(2)where X, Y, and Z are tristimulus values for either the 1931CIE standard o

    38、bserver (2 observer) or the 1964 CIE standardobserver (10 observer) and standard illuminant D65, or otherphase of daylight. These scales do not provide a perceptuallyuniform color space. Consequently, color differences are sel-dom if ever computed directly from differences in x, y, and Y.6.2 CIE 197

    39、6 L* a* b* Uniform Color Space and Color-Difference Equation (1, 6)This is an approximately uniformcolor space based on nonlinear expansion of the tristimulusvalues and taking differences to produce three opponent axesthat approximate the percepts of lightness-darkness, redness-greenness and yellown

    40、ess-blueness. It is produced by plottingin rectangular coordinates the quantities L*, a*, b*, calculatedas follows:L* 5 116 f QY! 2 16 (3)a* 5 500 f QX! f QY! (4)b* 5 200 f QY! f QZ! (5)where:QX5 X/Xn!; QY5 Y/Yn!; QZ5 Z/Zn!andFQi! 5 Qj1/3if Qj. 6/29!3elseFQi! 5 841/108!Qi1 4/29 if Qj# 6/29!3.Here, i

    41、 varies as X, Y, and Z.The tristimulus values Xn, Yn, Zndefine the color of thenominally white object-color stimulus. Usually, the whiteobject-color stimulus is given by the spectral radiant power ofone of the CIE standard illuminants, for example, C, D65oranother phase of daylight, reflected into t

    42、he observers eye bythe perfect reflecting diffuser. Under these conditions, Xn, Yn,Znare the tristimulus values of the standard illuminant with Ynequal to 100.6.2.1 The total color-difference DE*abbetween two colorseach given in terms of L*, a*, b* is calculated as follows:DE*ab5 =DL*!21 Da*!21 Db*!

    43、2(6)NOTE 1The color space defined above is called the CIE 1976 L* a *b* space and the color-difference equation the CIE 1976 L* a* b*color-difference formula. The abbreviation CIELAB (with all letterscapitalized) is recommended.6.2.2 The magnitude, DE*ab, gives no indication of thecharacter of the d

    44、ifference since it does not indicate the relativequantity and direction of hue, chroma, and lightness differ-ences.6.2.3 The direction of the color difference is described bythe magnitude and algebraic signs of the components DL*,Da*, and Db*:DL* 5 L*B2 L*S(7)Da* 5 a*B2 a*S(8)Db* 5 b*B2 b*S(9)where

    45、L*S, a*S, and b*Srefer to the reference or standard,and L*B, a*B, and b*Brefer to the test specimen or batch. Thesigns of the components DL*, D a*, and Db* have thefollowing approximate meanings (7):1DL* 5 lighter (10)2D L* 5 darker (11)1Da* 5 redder less green! (12)2Da* 5 greener less red! (13)1Db*

    46、 5 yellow less blue! (14)2D b* 5 bluer less yellow! (15)6.2.4 For judging the direction of the color differencebetween two colors, it is useful to calculate their CIE 1976metric hue angles haband CIE 1976 metric chroma C*abasfollows:hab5 tan2 1Sb*a*D(16)C*ab5 =a*!21 b*!2(17)Differences in hue angle

    47、habbetween the test specimen andreference can be correlated with differences in their visuallyperceived hue, except for very dark colors (8). Differences inchroma DC*a-b=(C*abbatchC*abstandard) can similarlybe correlated with differences in visually perceived chroma.6.2.5 For judging the relative co

    48、ntributions of differences inlightness, chroma, and hue to the total color difference betweentwo colors, it is useful to calculate the CIE 1976 metric huedifference DH*abbetween them as follows:DH*ab5 =DE*ab!22 DL*!22 DC*ab!2(18)where DE*abis calculated as in 6.2.1 and DC*abis calculatedas in 6.2.4;

    49、 then the equationDE*ab5 =DL*!21 DC*ab!21 DH*ab!2(19)contains terms showing the relative contributions of light-ness differenceD L*, chroma difference DC*ab, and hue differ-ence D H*abto the total color differenceD E*ab. This methodof computing a metric hue difference loses the informationabout the sign of the hue difference (positive or negative) andcan be unstable for pairs of colors near the neutral axis. Analternative method has been proposed (14) that corrects bothproblems:DH*ab5 s 2 C*ab,BC*ab,S a*Ba*S b*Bb*S!


    注意事项

    本文(ASTM D2244-2007e1 Standard Practice for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color Coordinates.pdf)为本站会员(priceawful190)主动上传,麦多课文档分享仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对上载内容本身不做任何修改或编辑。 若此文所含内容侵犯了您的版权或隐私,请立即通知麦多课文档分享(点击联系客服),我们立即给予删除!




    关于我们 - 网站声明 - 网站地图 - 资源地图 - 友情链接 - 网站客服 - 联系我们

    copyright@ 2008-2019 麦多课文库(www.mydoc123.com)网站版权所有
    备案/许可证编号:苏ICP备17064731号-1 

    收起
    展开