ASTM_D_2253_-_88_scan.pdf

-37-07 ASTM D2253 88 W 0759510 002qi79 O AMERICAN SOCIETY FOR TESTING AND MATERIALS 1916 Race St.,Philadelphia,Pa.19103 Reprinted from the Annual Book of ASTM Standards,Copyright ASTM If not listed in the current combined index,will appear In lhe next edition.Designation;D 2253-8 1 3 Standard Test Method for Color of Raw Cotton Using the Nickerson-Hunter Cotton Colorimeter This standard is issued under the f i x e d designation D 2253;the number immediately following the designation indicates the year of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicatesthe year of last reapproval.A superscript epsilon(E)indicates an editorial change since the last revision or reapproval.1.&ape 1.1 This test method covers the comparison of the color of raw cotton with the color of the official cotton standards of the United States of America for grade of cotton by means of a cotton colorimeter of the Nickerson-Hunter type(1,2).2 It can be used to measure the color of any type of raw cotton,but is particularly applicable to Upland and American Pima cotton and to cotton linters,for which official United States standards have been established.1.2 The colorimeter may be used to measure the color of other materials provided that a suitable specimen can be prepared and that the color of the material falls within the range of the instrument scales.1.3 The values stated in SI units are to be regarded as the standard.1.4 This standard may involve hazardous materials,oper-ations,and equipment.This standard does not purport to address all o f the safety problems associated with its use.It is the responsibility of the mer o f this standard to establish appropriate safety and health practices and determine the applicability o f regulatory limitations prior to use.2.Referenced Documents 2.1 ASTM Standards:D 123 Terminology Relating to Textiles3 D 144 1 Practice for Sampling Cotton Fibers for Testing3 D 1535 Method of Specifying Color by the Munsell System4 E 308 Method for Computing the Colors of Objects by Using the CIE System 3.Terminology 3.1 Definitions:3.1.1 raw cotton,n-ginned lint that has not been sub-jected to any textile manufacturing process.3.1.2 For definitions of other textile terms used in t h i s method,refer to Terminology D 123.3.2 Descriptions of Terms Specific to This Standard:3.2.1 color space-for the parpose o f this standard,the daylight color of opaque specimens represented by points in a space described in terms of three color s c a e s:(i)reflectance This test method is under the jurisdiction of ASTM Committee D-13 on Textiiw and i s the direct responsibility of Subcommittee D 13.1 1 on Cotton Fikrs.Current edition approved Feb.26,1988.Published April 1988.Originally published as D 2253-64 T.Last previous edition D 2253-81.The boldface numbers in parentheses refer to references listed at the end of this test method.Annual Book 0fAST.N Sandards,Vol 01.02.Annual Book OfASiSiandards,Vol 06.01.AnnwlBwk o/ASMsfandards,Vol 14.02.&,(2)the chromaticity coordinates for redness or greenness,fa,and(3)the chromaticity coordinates-of yellowness or blueness Ib.3.2.1.1 Discussion-Color space may be represented by three mutually perpendicular unit vectors in which R d is represented vertically,and the chromaticity coordinates a and b are represented on a horizontal plane at right angles to each other.In the range of R d for colors observed in cotton,the d e s of the cotton colorimeter show a reasonably close relationship to the uniform perceptual spacing of the scales represented in the Munsell color space which is described in Method D 1535.For further discussion,see Hunter,Ref(3).4.Summary of Test Method 4.1 The color of raw cotton is measured with a colorimeter designed especially for this purpose!A smooth representative surface of a cotton sample is placed over the sample window,the cotton is pressed flat,the instrument is energized,the indicators move to a balance point under the color diagram,and the color is read directly from the color diagram in one or more of the following terms:(1)the color of the most similar cotton grade standard,(2)the Grayness and Yellow-ness scale developed for cotton,(3)the R d and+b scales.5.Uses and Significance 5.1 This test method for color of raw cotton may be used for acceptance testing of commerical shipments since the bias between laboratories if any is usually small and may be determined easiiy.5.1.1 In case of a dispute arising from differences in re-ported test results when using Test Method D 2253 for ac-ceptance testing of commercial shipments,the purchaser and the supplier should conduct comparative tests to determine if there is a statisticai bias between their laboratories.Com-petent statistical assistance is recommended for the investi-gation of bias.As a minimum,the two parties should take a group of test specimens that are as homogeneous as possible and that are from a lot of material of the type in question.The test speci