1、Designation: D6961/D6961M 09Standard Test Method forColor Measurement of Flax Fiber1This standard is issued under the fixed designation D6961/D6961M; the number immediately following the designation indicates theyear of original adoption or, in the case of revision, the year of last revision. A numb
2、er in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the instrumental color measure-ment of flax fiber.1.2 The values stated in either SI units or inch-pound unitsare t
3、o be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.3 This standard does not purport to address all of
4、 thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D123 Terminology Relatin
5、g to TextilesD1776 Practice for Conditioning and Testing TextilesD6798 Terminology Relating to Flax and LinenE284 Terminology of AppearanceE308 Practice for Computing the Colors of Objects byUsing the CIE SystemE1164 Practice for Obtaining Spectrometric Data forObject-Color Evaluation2.2 Other Stand
6、ard:AATCC Evaluation Procedure 6 Instrumental Color Mea-surement33. Terminology3.1 Definitions:3.1.1 water retting, vin flax, the process of immersing flaxstraw for a period of time in water to effect retting.3.1.2 dew retting, vin flax, the process of pulling orcutting flax straw and leaving on the
7、 soil for a period of timeto allow partial degradation of straw to effect retting.3.1.3 enzyme retting, vin flax, the process of mechanicallyadding enzyme formulations under precise conditions to pulledor cut flax straw for a period of time to effect retting.3.2 For definitions of other textile term
8、s used in this testmethod, refer to Terminologies D6798 and D123.4. Summary of Test Method4.1 Samples of flax fiber are presented to a color spectro-photometer. Color measurements are taken through a largeaperture port 25.4 millimeter (1-in.) diameter, in order toaverage over the natural color varia
9、tion that occurs in flax fiber.The instrument aperture is fitted with a quartz window. Thewindow serves two functions, namely, to provide a base forcompacting the sample during measurement, and to protect theinstrument from accumulation of stray fiber particles. CIELABL*, a*, and b* measurements are
10、 taken and are instrumentallycalculated from tristimulus X, Y and Z data, observer function,and illuminant data.5. Significance and Use5.1 Few standards exist to objectively judge flax quality.Color is an important factor in the quality of flax fiber. Naturalvariations in raw flax fiber, various pro
11、cessing steps, fiberblending, and a wide range of end uses contribute to the needfor a standard method of objectively measuring the color offlax fiber. Spectrophotometic data provide an accurate, precisedetermination of the color of flax fiber. Colorimetric data areobtained through specimen measurem
12、ent by combining speci-men spectral data with data representing a CIE standardobserver and a CIE standard illuminant, as described inMethod E308.5.2 If there are differences of practical significance betweenreported test results for two (or more) laboratories, compara-tive tests should be performed
13、to determine if there is astatistical bias between them, using competent statistical assis-tance. As a minimum, use the samples for such a comparativetest that are as homogeneous as possible, drawn from the samelot of material as the samples that resulted in disparate results1This test method is und
14、er the jurisdiction of ASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.17 on Flax and Linen.Current edition approved July 1, 2009. Published December 2009. Originallyapproved in 2003. Last previous edition approved in 2003 as D696103. DOI:10.1520/D6961-09.2For refe
15、renced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American Association of Textile Chemists and Colorists
16、(AATCC), P.O. Box 12215, Research Triangle Park, NC 27709, http:/www.aatcc.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.during initial testing and randomly assigned in equal numbersto each laboratory. The results from the labo
17、ratories involvedshould be compared using a statistical test for unpaired data, aprobability level chosen prior to the testing series. If a bias isfound, either its cause must be found and corrected, or futuretest results for that fiber sample type must be adjusted inconsideration of the known bias.
18、6. Apparatus6.1 A visible range spectrophotometer (minimum of 20-point) is recommended. Such an instrument provides greateraccuracy than colorimeters, spectro-colorimeters, or 10-pointcolor spectrophotometers.6.1.1 Instrument Configuration and Settings:46.1.1.1 Either a 0/45 or a spherical instrumen
19、t/specimengeometry may be used. The selected geometry should beincluded in the report.6.1.1.2 If the instrument offers a choice of specular modes,measurements should be taken using the specular excludedmode.6.1.1.3 Use the recommended CIE Illuminant D65 unlessotherwise specified in a material specif
20、ication or contract order.If an alternate illuminant is selected, its specifications shouldbe included in the report.6.1.1.4 Use the recommended CIE 10-degree observer un-less otherwise specified in a material specification or contractorder. If an alternate illuminant is selected, its specifications
21、should be included in the report.6.2 A fiber compression cell capable of applying air pres-sure of 206,843 Pa (30 psi) or 275,790 Pa ( 40 psi ) isrecommended for assuring consistent pressure among speci-mens presented for measurement.7. Sampling and Sample Preparation7.1 For acceptance testing, take
22、 a lot of sample fromshipping containers as directed in an applicable specification,or as agreed upon between the purchaser and supplier.7.2 Take the measurement at a minimum of five sites withina specimen and three measurements at each site. Means of thethree readings constitute the site reading. F
23、or each specimen,report means of the five site readings.7.3 Sample Handling and Preparation:7.3.1 In addition to natural color variation within a sample,other variables that may influence color measurements includefiber orientation within the sample, and the relative compact-ness of the sample. With
24、 a flax sample there may be consid-erable variation in fiber orientation. Some specimens may betotally randomly oriented, while in some specimens there maybe areas in which fibers are parallel. In selecting measurementsites, care should be taken to avoid areas in which there areobvious changes in fi
25、ber orientation that could result inshadows that might contribute to error in measurement.7.3.2 Users are advised that moisture may influence color offlax and linen. Samples should be conditioned prior to mea-surement, as described in Practice D1776.7.3.3 Bundles of flax fiber presented for measurem
26、ent arerather open-structured, capable of being easily compactedthrough pressure. Care should be taken in applying the samepressure to samples during measurement, because the densityof the sample may influence readings. The sample should becompressed firmly against the glass-covered aperture to assu
27、rethat the entire aperture is covered by fiber. Consistency inpressure can be achieved through the use of a fiber compres-sion cell that consists of a cup fiber specimen holder and clampthat is pressed against the specimen through application ofcompressed air. Air pressure of 206,843 Pa (30 psi) or
28、275,790Pa ( 40 psi ) is recommended.8. Procedure8.1 Specimens are compressed at a pressure of 206,843 Pa(30 psi) or 275,790 Pa ( 40 psi ) and presented to the instrumentaperture so that the entire area of the aperture is filled with thespecimen.8.2 CIELAB L*, a*, and b* measurements are taken at ami
29、nimum of five sites within a specimen, and three measure-ments are taken at each site. Specimens are repacked androtated 90 between each of the three measurements taken atone site to reduce variability with respect to fiber orientation.Means of the three readings constitute the site reading.9. Calcu
30、lation9.1 Means of the five site readings per specimen of CIELABL*, a*, and b* are calculated. These readings indicate variationin lightness (L*), redness-greenness (a*), and yellowness-blueness (b*).9.2 Calculations of differences in lightness, in redness-greenness, and yellowness-blueness between
31、specimens maybe reported as DL*, Da*, and Db* values. Overall colordifferences, DE*, may also be calculated , where DE CIELAB=DL*2+ Da*2+ and Db*21/2.10. Report10.1 State that the specimens were measured as directed inASTM Test Method D6961.10.2 Report means of five site readings of CIELAB L*. a*,an
32、d b*.10.3 Report instrument manufacturer and model.10.4 Report illuminant/specimen geometry of the instru-ment.10.5 Report instrument settings, including the illuminant,observer function, and specular mode.4All available apparatus may not be suitable for this application. Apparatusconsidered for use
33、 in this application shall be checked for suitability in accordancewith the requirement of Method E308.TABLE 1 Summary of precision and bias analysis for CIELAB L*SampleAveragexRepeatabilityStandardDeviationsrReproducibilityStandardDeviationsRRepeatabilityLimitrReproducibilityLimitR1 59.03 2.1655 8.
34、7004 6.0633 24.36122 53.24 1.0664 6.9831 2.9860 19.55263 51.81 2.9932 8.3534 8.3810 23.38964 56.23 4.3230 8.9706 12.1043 25.11775 58.64 1.0370 6.6149 2.9036 18.52176 54.81 0.3935 5.1631 1.1018 14.4568D6961/D6961M 09210.6 Report pressure under which the specimens werecompressed during measurement.11.
35、 Precision and Bias11.1 PrecisionThe average, standard deviation, and 95 %repeatability limit (2.8X sample standard deviation) of inter-laboratory samples tested with the same method for variousflax fiber samples are shown in Table 1, Table 2, and Table 3.11.2 BiasWith the limitation imposed by the
36、lack of flaxfiber color reference standards, this test method has no knownbias.12. Keywords12.1 CIELAB; color; flax fiberASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expres
37、sly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised,
38、 either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may at
39、tend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States.
40、 Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be sec
41、ured from the ASTM website (www.astm.org/COPYRIGHT/).TABLE 2 Summary of precision and bias analysis for CIELAB a*SampleAveragexRepeatabilityStandardDeviationsrReproducibilityStandardDeviationsRRepeatabilityLimitrReproducibilityLimitR1 2.87 0.1393 0.4673 0.3902 1.30842 2.90 0.0854 0.4837 0.2391 1.354
42、33 2.97 0.1373 0.5212 0.3844 1.45934 2.95 0.2137 0.5185 0.5984 1.45185 2.83 0.0535 0.4271 0.1498 1.19606 5.31 0.1764 0.7411 0.4939 2.0750TABLE 3 Summary of precision and bias analysis for CIELAB b*SampleAveragexRepeatabilityStandardDeviationsrReproducibilityStandardDeviationsRRepeatabilityLimitrReproducibilityLimitR1 12.81 0.4700 2.0691 1.3160 5.79332 12.77 0.1721 2.1517 0.4819 6.02483 11.23 0.3604 2.0252 1.0092 5.67074 8.69 0.7160 5.5004 2.0048 15.40125 12.61 0.1345 1.7626 0.3767 4.93556 19.33 0.6487 3.7622 1.8165 10.5341D6961/D6961M 093
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