ASTM_C_1650_-_14.pdf

Designation:C165014Standard Practice forInstrumental Reflectance Measurement of Color for FlatGlass,Coated,and Uncoated1This standard is issued under the fixed designation C1650;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.1.Scope1.1 This practice provides guidelines for the instrumentalreflectance measurement of the color of flat,coated anduncoated glass.See Terminology E284.1.2 The practice specifically excludes fluorescent and iri-descent samples.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.4 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:2D2244 Practice for Calculation of Color Tolerances andColor Differences from Instrumentally Measured ColorCoordinatesE284 Terminology of AppearanceE179 Guide for Selection of Geometric Conditions forMeasurement of Reflection and Transmission Propertiesof MaterialsE308 Practice for Computing the Colors of Objects by Usingthe CIE SystemE1164 Practice for Obtaining Spectrometric Data for Object-Color EvaluationE1331 Test Method for Reflectance Factor and Color bySpectrophotometry Using Hemispherical Geometry2.2 CIE Standard:3CIE 15:2004 Colorimetry,Third Edition3.Summary of Practice3.1 The reflected color of glass products,(see Guide E179)is measured in reflectance specular included mode on aCIE-conforming diffuse geometry instrument.(See TestMethod E1331 and CIE 15:2004.)The glass color is expressedin CIE tristimulus values based on spectral transmittancemeasurements over the full CIE spectral range of 350 780 nmwith a maximum 10-nm band pass.(See CIE 15:2004 andPractice E308.)For color measurement,use of a truncatedspectral range of 400 700 nm is acceptable.(See CIE15:2004.)Further information on the UV absorbing character-istics of the glass or glass coating,or both,may be determinedby examining the spectral data in the 350 400 nm range.Ifthe instrument allows spectral measurement above 700 nm,useful information on the IR reflectance characteristics of theglass coating may also be determined.If coatings are present,they can be opaque or partially reflective.4.Significance and Use4.1 Color measurement quantifies the coating color for glassand is often related to coating thickness and composition aswell as tinting used in the substrate glass.The user of thisdocument defines an acceptable range of color appropriate forthe end use.Typical quality concerns for the reflected colormeasurement of coated glass products are an indication ofconsistency in the coating process and verification of lot-to-lotcolor consistency for end-user acceptance.4.2 If the reflected color of a glass product is consistentfrom lot-to-lot and within agreed supplier-buyer acceptancecriteria,that product color is expected to be consistent andacceptable for end-use.5.Apparatus5.1 For color measurements,a CIE-conforming diffusegeometry instrument capable of making reflectance measure-ments in the specular included mode is required.1This practice is under the jurisdiction of ASTM Committee C14 on Glass andGlass Products and is the direct responsibility of Subcommittee C14.11 on OpticalProperties.Current edition approved May 1,2014.Published May 2014.Originallyapproved in 2007.Last previous edition approved in 2007 as C1650 07.DOI:10.1520/C1650-14.2For 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.3Available from CIE Commission Internationale de LEclairage,Wien,Austria,www.cie.co.at.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.2 A fixture device is required to consistently place thesample at the reflection port.5.3 To prevent transmitted signal from being part of themeasurement,a light trap capable of being mounted behind theglass sample at the reflectance port may be required to measurepartially reflective coatings.5.4 The instrument and associated color quality software/firmware shall be capable of converting measured spectralreflectance data to CIE L*,a*b*;Hunter L,a,b;or Y x,yvalues calculated for CIE illuminant D65 and the CIE 1964 10degree standard observer.(See Practice E1164.)Any of thesemappings will serve as a full numerical color descriptor.(SeePractice E308.)CIE Y luminosity can also serve as an over-allindicator of reflectance.For other illuminant/observercom