ASTM E313-20 Standard Practice for Calculating Yellowness and Whiteness Indices fromlnstrumentally Measured Color Coordinates

Designation: E313-20 Standard Practice for Calculating Yellowness and Whiteness Indices fromlnstrumentally Measured Color Coordinates1 1. Scope 1.1 This practice provides numbers that correlate withvisual ratings of yellowness or whiteness of white and near-white or colorless object-color specimens.viewed in daylightby an observer with normal color vision. White textiles, paints.and plastics are a few of the materialls that can be described bythe indices of yellowness or whiteness calculated by thispractice. 1.2 For a complete analysis of object colors, by a specifiedobserver and under a specified illuminant, use of three param-eters is required. For near-white specimens, however, it is ofltenuseful to calculate single-number scales of yellowness orwhiteness.This practice providles recommended equations forsuch scales and discusses their derivations and uses.and limitsto their applicability (see also Ref (10. 1.3 The values stated in Sl units are to be regarded as standard. No other units of measurement arc included in thisstandard. 1.4 This standard does nor purport vo address all of thesafety concernas，if ary, associated wirh irs use. It is rheresponsibility of the user of this siandard to establish appro-pricte seafery， healha,and erivironnientcal practices and deter-rine rhe applicebiliry of regulctory liirations prior to use. 1.5 This inrerracrional sranrdard was developed inx accor-eance with inrerracrionally recognized principles o stavdcrd-izarion esiablishedd in the Decisiow on Principles for theDevelopmenr of Interniational Srandards，Guides and Recom-mevddatios issueed by the World Trade Organization TechnicalBarriers ro Trade (TBT) Connitsee. E313-20 Standard Practice for Calculating Yellowness and Whiteness Indices fromlnstrumentally Measured Color Coordinates