ASTM_E_1455_-_16.pdf

Designation:E145516Standard Practice forObtaining Colorimetric Data from a Visual Display UnitUsing Tristimulus Colorimeters1This standard is issued under the fixed designation E1455;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 parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.INTRODUCTIONThis practice provides directions for correcting the results obtained with tristimulus colorimeterswhen measuring the tristimulus values or chromaticity coordinates of colored displays.Tristimuluscolorimeters approximate the CIE color matching functions x(),y(),z()to make these measure-ments.The errors generated in measuring colors on a display may be minimized using this practice.1.Scope1.1 This practice is intended as an aid for improving theaccuracy of colorimetric measurements made with tristimuluscolorimeters on visual display units,such as cathode ray tubes(CRTs)and self-luminous flat-panel displays.It explains auseful step in the analysis of colorimetric data that takesadvantage of the fact that light from such displays consists ofan additive mixture of three primary colored lights.However,it is not a complete specification of how such measurementsshould be made.1.2 This practice is limited to display devices and colori-metric instruments that meet linearity criteria as defined in thepractice.It is not concerned with effects that might causemeasurement bias such as temporal or geometric differencesbetween the instrument being optimized and the instrumentused for reference.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-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E284 Terminology of AppearanceE1336 Test Method for Obtaining Colorimetric Data From aVisual Display Unit by SpectroradiometryE1341 Practice for Obtaining Spectroradiometric Data fromRadiant Sources for Colorimetry2.2 ISO/CIE Standard:ISO 116641:2007(E)/CIE S 0141/E:2006 Joint StandardISO/CIE Standard:Colorimetry Part 1 CIE StandardColorimetric Observers33.Terminology3.1 DefinitionsUnless otherwise stated,definitions of ap-pearance terms in Terminology E284 are applicable to thispractice.3.2 Definitions of Terms Specific to This Standard:3.2.1 calibration,ninreferencetoatristimuluscolorimeter,the process performed outside of this practice toadjust the tristimulus colorimeter to provide the best possibleresults for average or predefined conditions.3.2.2 optimization,nin reference to a tristimuluscolorimeter,the process performed pursuant to this practice toadjust the tristimulus colorimeter or to interpret its readings toprovide better results when applied to a particular displaydevice.3.2.3 compatible,adjin reference to a tristimuluscolorimeter,one so designed as to automate the proceduredescribed in this practice.4.Summary of Practice4.1 Tristimulus colorimeters comprised of three or fourdetector channels are,in general,not amenable to accuratecalibration that holds for all manner of usage with different1This practice is under the jurisdiction of ASTM Committee E12 on Color andAppearance and is the direct responsibility of Subcommittee E12.06 on Display,Imaging and Imaging Colorimetry.Current edition approved July 1,2016.Published August 2016.Originallyapproved in 1992.Last previous edition approved in 2010 as E1455 03(2010).DOI:10.1520/E1455-16.2For 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 onthe ASTM website.3Currently available from CIE(Commission International on Illumination),http:/.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 illuminated devices and objects.This is because the spectralresponsivities of their detector channels do not exactly matchthe defined Commission Internationale de Lclairage(CIE)x(),y(),z()functions.Factory or subsequent calibrationreflects judgments and compromises that may not be readilyapparent.Nevertheless,this practice provides guidance on howsuch a tristimulus colorimeter may be optimized for use with aparticular video display device,providing better accuracy withthat device than its more general calibration provides.Anoptimization matrix transforms the instrumental(measured)CIE X,Y,Z values into adjusted X,Y,Z values that are closerto the ideal.This matrix is determined by reference to acolorimeter with higher intrinsic accuracy.The method derivesfrom the fact that the color stimulus functions from displaydevices are linear combinations of three primary functions andare not