ASTM_D_985_-_97_2002.pdf

Designation:D 985 97(Reapproved 2002)An American National StandardStandard Test Method forBrightness of Pulp,Paper,and Paperboard(DirectionalReflectance at 457 nm)1This standard is issued under the fixed designation D 985;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(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method determines the brightness of white,near-white,and naturally colored pulp,paper,and paperboard.Brightness is a commonly used industry term for the numericalvalue of the reflectance factor of a sample,with respect to bluelight of specific spectral and geometric characteristics.This testmethod requires an instrument employing 45 illumination and0 viewing geometry,with the illuminating and viewing beamsadjusted so that translucent materials are evaluated on anarbitrary but specific scale(1-4).21.2 This test method is applicable to all naturally-coloredpulps,and papers and board made from pulps.The measure-ment is not suitable for paper and paperboard containing addedcoloring matter(such as yellow or green dyestuff)whichappreciably absorbs light in that part of the spectrum extendingfrom about 400 to 500 nm.Colored papers must be measuredspectrophotometrically or colorimetrically in order to obtainmeaningful results(TAPPI T442,T524,and T527).This testmethod is,however,suitable for pulps or papers which containoptical(fluorescent)brightening agents.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:D 585 Practice for Sampling and Accepting a Single Lot ofPaper,Paperboard,Fiberboard,and Related Products3D 1968 Terminology Relating to Paper and Paper Products32.2TAPPI Standards:T 218 Forming handsheets for reflectance tests of pulp4T 442 Spectral reflectance factor,transmittance and color ofpaper and pulp(Polychromatic illumination)4T 452 Brightness of pulp,paper and paperboard(Direc-tional reflectance of 457 nm)4T 524 Color of white and near-white paper and paperboardby L,a,b 45 0 colorimetry4T 527Color of paper and paperboard in CIE system4T 1206 Precision statements for test methods43.Terminology3.1 DefinitionsDefinitions shall be in accordance withTerminology D 1968 and the Dictionary of Paper.44.Summary of Test Method4.1 This test method provides the following:4.1.1 A scale for measurement of paper brightness(bluedirectional reflectance factor),4.1.2 A method for verifying the calibration of each instru-ment used for brightness testing so that the user can rely uponthe test results,and4.1.3 Criteria for the geometric,and photometric character-istics required by instruments employed in the use of this testmethod.4.2 A procedure is also described for separating the fluores-cent component of brightness from the non-fluorescent com-ponent of brightness and measuring it quantitatively.5.Significance and Use5.1 Brightness is the most extensively used optical propertyof pulp,paper,and paperboard.The measurement of brightness(blue reflectance)was originally devised as a means ofquantitatively assessing the effectiveness of pulp bleaching.Aspecific spectral response has been defined and rigorouslymaintained,providing longterm stability of brightness valuesto the industry.5.2 The accurate determination of brightness is of vitalimportance in the buy-sell relationship between the paperproducer and consumer.High brightness is an indication of1This test method is under the jurisdiction of ASTM Committee D06 on Paperand Paper Products and is the direct responsibility of Subcommittee D06.92 on TestMethods.Current edition approved Dec.10,1997.Published October 1998.Originallyapproved in 1948.Last previous edition approved in 1993 as D 985 93.2The boldface numbers in parentheses refer to the list of references at the end ofthis test method.3Annual Book of ASTM Standards,Vol 15.09.4Available from the Technical Association of the Pulp and Paper Industry,P.O.Box 105113,Atlanta,GA 30348.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.high-quality paper,resulting in a price structure where price isrelatively proportional to the brightness level.Paper producersare required to employ additional bleaching or the addition ofcostly optical brighteners in order to obtain high-brightnesspaper.The high cost of such brightening materials mandatesadherence to close production tolerances for the brightness ofthe end product.6.Apparatus6.1 Brightness TesterA test instrument which embodiesthe geometric and spectral characteristics specified in AnnexA1 and in such adjustment that its c