ASTM_D_589_-_97_2002.pdf

Designation:D 589 97(Reapproved 2002)An American National StandardStandard Test Method forOpacity of Paper(15 Diffuse IlluminantA,89%ReflectanceBacking and Paper Backing)1This standard is issued under the fixed designation D 589;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 covers the determination of the opacityof paper.1.2 Two different types of“white”backing are specified,leading to two different opacity values,in accordance withSection 3.1.3 This test method employs 15 diffuse geometry,Illumi-nant A/2 and 89%reflectance backing or paper backing.Forthe measurement of opacity with d/0 geometry,IlluminantC/2 and paper backing(see TAPPI T 519).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:D 585 Practice for Sampling and Accepting a Single Lot ofPaper,Paperboard,Fiberboard,and Related Product2D 646 Test Method for Grammage of Paper and Paperboard(Mass Per Unit Area)2D 685 Practice for Conditioning Paper and Paper Productsfor Testing2D 1968 Terminology Relating to Paper and Paper Products2E 122 Practice for Calculating Sample Size to Estimate,with a Specified Tolerable Error,the Average for Charac-teristic of a Lot or Process3E 308 Practice for Computing the Colors of Objects byUsing the CIE System42.2TAPPI Standards:TAPPI Technical Information Sheet 0804-03Interrelationof reflectance,R0;reflectivity,R;TAPPI opacity,C0.89scattering,s;and absorption,k5TAPPI Technical Information Sheet 0804-06Photometriclinearity of optical properties instruments5T 519 Diffuse opacity of paper(d/0 paper backing)5T 1206 Precision statement for test methods53.Terminology3.1 Definitions:Definitions:3.1.1 Definitions shall be in accordance with Terminology D1968 and the Dictionary of Paper.53.2 Definitions of Terms Specific to This Standard:3.2.1 opacity(89%reflectance backing),C0.89one hun-dred times the ratio of the diffuse reflectance,R0,of a specimenbacked by a black body of 0.5%reflectance or less to thediffuse reflectance,R0.89,of the same specimen backed with awhite body having an absolute reflectance of 0.89;thus,C0.89=100 R0/R0.89.Accordingly,the contrast ratio is 100%for perfectly opaque paper and is only a few percent forperfectly transparent sheets.(Sometimes called contrast ratio.)4.Summary of Test Method4.1 The reflectance of paper when combined with a whitebacking is higher than that of paper when combined with ablack backing because in the former case,light transmittedthrough the imperfectly opaque sheet is largely reflected by thewhite backing,and a portion of the light thus reflected istransmitted through the paper a second time.Two types of“white”backing are used,leading to the two measurements ofopacity defined in Section 3.5.Significance and Use5.1 Opacity is a fundamental optical property of paper as awhole,yet the measurement of opacity is empirical.Theopacity of the sheet is influenced by the amount and kind offiller,degree of bleaching of the fibers,coating,and the like.The utility of bond,writing,and book papers may be enhancedby a high opacity.1This 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 November 1998.Originallyapproved in 1940.Last previous edition approved in 1994 as D 589 94.2Annual Book of ASTM Standards,Vol 15.09.3Annual Book of ASTM Standards,Vol 14.02.4Annual Book of ASTM Standards,Vol 06.01.5Available from the Technical Association of the Pulp and Paper Industry,Technology Park/Atlanta,P.O.Box 105113,Atlanta,GA 30348.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.5.2 The determination of opacity is of vital importance toboth the manufacturer and the consumer.When white pigmentis added to a sheet,it scatters more light,and thus increasesopacity;however,it is also possible to increase opacity of asheet by adding dark pigment or dye which absorbs light.Thisbeing so,it is of value to the manufacturer,in meeting anopacity specification,to be able to predict whether a sheetwhich does not have desired opacity can be brought up tospecification by raising or,alternatively,lowering the reflec-tivity within permissible limits.To the consumer,opacitymeasurements are used to evaluate some of the characteristicsof appearance.The user is interested in the comparison ofsamples under identical conditions.When comparisons aremade,one sample with an