1、Designation: D 6961 03Standard Test Method forColor Measurement of Flax Fiber1This standard is issued under the fixed designation D 6961; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parent
2、heses indicates the year of last reapproval. Asuperscript epsilon (e) 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 UnitsThe values stated in either SI units or inch-pound units (which are
3、 provided in parentheses). The valuesstated in each system may not be exact equivalents; therefore,each system shall be used independently of the other. Combin-ing values from the two systems may result in non-conformance with the standard.1.3 This standard does not purport to address all of thesafe
4、ty 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:2D 123 Terminology Related to Tex
5、tilesD 1776 Practice for Conditioning and Testing TextilesD 6798 Terminology Relating to Flax and LinenE 284 Terminology of AppearanceE 308 Method for Computing the Colors of Objects byUsing the CIE SystemE 1164 Practice for Obtaining Spectrophotometric 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 D 6798 and D 123.4. 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-inch) diameter, in order toaverage over the natural color va
9、riation 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
10、are 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
11、processing 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 measu
12、rement by combining speci-men spectral data with data representing a CIE standardobserver and a CIE standard illuminant, as described inMethod E 308.5.2 If there are differences of practical significance betweenreported test results for two (or more) laboratories, compara-tive tests should be perfor
13、med 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 resultsduring initial testi
14、ng and randomly assigned in equal numbersto each laboratory. The results from the laboratories involvedshould be compared using a statistical test for unpaired data, a1This test method is under the jurisdiction of ASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.17
15、on Flax and Linen.Current edition approved Oct. 1, 2003. Published November 2003.2For referenced 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
16、 onthe ASTM website.3Available from American Association of Textile Chemists and Colorists(AATCC), One Davis Dr., P.O. Box 12215, Research Triangle Park, NC 27709-2215.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.probability level
17、 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.6. Apparatus6.1 A visible range spectrophotometer (minimum of 20-point) is recommended. Such an in
18、strument 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 instrument/specimengeometry may be used. The selected geometry should beincluded in the report.6.1.1.2 If t
19、he 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 specification or contract order.If an alternate illuminant is selected, its specifications shouldbe incl
20、uded 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 specificationsshould be included in the report.6.2 A fiber compression cell capable of applying air pres-sure of
21、 2.1 to 2.8 kg/cm2(30 to 40 psi ) is recommended forassuring consistent pressure among specimens presented formeasurement.7. Sampling and Sample Preparation7.1 For acceptance testing, take a lot of sample fromshipping containers as directed in an applicable specification,or as agreed upon between th
22、e 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. For each specimen,report means of the five site readings.7.3 Sample Handling and Preparation:7.3.1 In addition to
23、 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 a flax sample there may be consid-erable variation in fiber orientation. Some specimens may betotally randomly
24、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 fiber orientation that could result inshadows that might contribute to error in measurement.7.3.2 Users are advise
25、d that moisture may influence color offlax and linen. Samples should be conditioned prior to mea-surement, as described in Practice D 1776.7.3.3 Bundles of flax fiber presented for measurement arerather open-structured, capable of being easily compactedthrough pressure. Care should be taken in apply
26、ing 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 assurethat the entire aperture is covered by fiber. Consistency inpressure can be achieved through the use of a fib
27、er 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 2.1 to 2.8 kg/cm2(30 to 40 psi)is recommended.8. Procedure8.1 Specimens are compressed at a pressure of 2.1 to 2.8kg/cm2(30 to 40 psi)
28、 and presented to the instrument apertureso that the entire area of the aperture is filled with thespecimen.8.2 CIELAB L*, a*, and b* measurements are taken at aminimum of five sites within a specimen, and three measure-ments are taken at each site. Specimens are repacked androtated 90 between each
29、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. Calculation9.1 Means of the five site readings per specimen of CIELABL*, a*, and b* are calculated. These readings indicate variationin lightn
30、ess (L*), redness-greenness (a*), and yellowness-blueness (b*).9.2 Calculations of differences in lightness, in redness-greenness, and yellowness-blueness between specimens maybe reported as DL*, Da*, and Db* values. Overall colordifferences, DE*, may also be calculated , where DE CIELAB=DL*2+ Da*2+
31、 and Db*21/2.10. Report10.1 State that the specimens were measured as directed inASTM Test Method D 6961.4All available apparatus may not be suitable for this application. Apparatusconsidered for use in this application shall be checked for suitability in accordancewith the requirement of Method E 3
32、08.TABLE 1 Mean, Standard Deviation, and Within-laboratoryRepeatability LimitASample TypeBStatistic L* a* b*Dew retted-1 Mean 59.66 2.51 10.90sd 0.36 0.08 0.24rl 1.00 0.24 0.69Dew retted-2 Mean 59.798 2.52 11.31Sd 0.64 0.07 0.27rl 1.80 0.20 0.76Dew retted-3 Mean 61.42 2.72 10.46sd 0.39 0.03 0.13rl 1
33、09 0.09 0.36Water retted Mean 65.51 2.92 13.69sd 0.52 0.32 0.69rl 1.45 0.89 1.92Enzyme retted Mean 72.90 3.63 18.10sd 0.91 0.20 0.59rl 2.54 0.55 1.66AThe and average and standard deviation (sd) are from 5 sites as described in8.2. The 95 % repeatability limit (rl) is derived by multiplying 2.8 3 th
34、e sample sdin accordance with Form and Style of ASTM Standards, section A21.2.5.BSamples are as follows: dew retted 1 is scutched flax, dew retted 2 is scotchedand hackled flax, dew retted 3 is cottonized flax, water retted is scutched andhackled flax, enzyme retted is an experimental sample that wa
35、s hand-cleaned.D696103210.2 Report means of five site readings of CIELAB L*. a*,and 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.10.6 Report
36、pressure under which the specimens werecompressed during measurement.11. Precision and Bias11.1 PrecisionThe average, standard deviation, and 95 %repeatability (2.8 3 sample standard deviation) of within-laboratory samples tested with the same method, equipment,laboratory, and operator under the sho
37、rtest time possible (about1 h) for samples of flax fiber retted by various means are shownbelow in Table 1. These measurements were taken with aspherical geometry, 20-point spectrophotometer, illuminantD-65, 10-degree observer, 25.4 mm (1-in.) aperture, withspecimen pressure of 2.1 kg/cm2(30 psi).11
38、2 BiasWith the limitation imposed by intralaboratoryevaluation, this test method has no known bias.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 thi
39、s standard are expressly 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 yea
40、rs andif not revised, 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 commit
41、tee, which you may attend. 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. 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).D6961033
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