ASTM_D_2019_-_97_2002.pdf

Designation:D 2019 97(Reapproved 2002)An American National StandardStandard Test Method forDirt in Paper and Paperboard1This standard is issued under the fixed designation D 2019;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(1,2,3)2is intended for the numericalestimation of dirt in paper or paperboard in terms of equivalentblack area.This test method is satisfactory only for theestimation of visual dirtiness and it may be entirely inadequatewhen the grittiness or other nonvisual effects of dirt are ofimportance.2.Referenced Documents2.1 ASTM Standards:D 585 Practice for Sampling and Accepting a Single Lot ofPaper,Paperboard,Fiberboard,and Related Product3D 985 Test Method for Brightness of Pulp,Paper,andPaperboard(Directional Reflectance at 457 nm)3D 1968 Terminology Relating to Paper and Paper Products33.Terminology3.1 DefinitionsDefinitions shall be in accordance withTerminology D 1968 and the Dictionary of Paper.44.Summary of Test Method4.1 Adirt speck is compared with black spots on a standard“dirt chart,”and the area of the black spot that gives the samevisual impression as the dirt speck is recorded.The sum of allsuch areas(known as equivalent black areas,or e.b.a.)that are0.04 mm2or greater is divided by the total area of the paperinspected.The result,expressed in parts per million,is used asa measure of the dirt in paper or paperboard.5.Significance and Use5.1 While dirt in paper is usually that found on the surfaceof the sheet,some particles embedded in the body of the sheetmay be readily discernible,especially in papers that aretransparent or translucent.Therefore,as a property,dirt contentmay affect both the utility and composition of the sheet.Theamount of dirt present in a sheet of paper is of importance inpractically every type of paper,but especially so in thehigher-quality products.For example,bond and fine writingpapers are subject to close inspection for dirt content,and theamount of dirt present in the sheet is one of the factors inclassifying them into different grades.5.2 The higher grades of wrapping papers and paperboards,such as those employed for the packaging of foods or othercommodities or where a fancy printed design is used,must befree of dirt particles.The value of many papers,such asglassine,waxed sulfite,and vegetable parchment,which comein direct contact with foodstuffs,is determined to a consider-able extent by the amount of dirt present in the sheet.5.3 Dirt in the form of fine gritty particles embedded in asheet of paper is a serious defect in many printing papers.Thistype of dirt may cause serious pitting and wear on the printingplates and other parts of the presses.Such gritty particles areoften termed“sand spots”in jute linerboard and cause amarked reduction in Mullen burst tests when they occur in thetest area.Measurement of dirt content in a sheet based on theequivalent area may be entirely inadequate in such cases,sincethe dirt is not readily detected nor is its equivalent area a goodcriterion of the suitability of the sheet for the purpose intended.6.Apparatus6.1 Standard Dirt Chart4A standardized photographicprint of a series of round black spots of various areas on a whitebackground.Using an instrument and method in accordancewith Method D 985,Test for 45-deg.0-deg Directional Reflec-tance for Blue Light(Brightness)of Paper,4with luminousreflectance filter,the Y value for Illuminant C of the CIEsystem is 81.5 6 1.0%reflectance for the white backgroundand 2.4 6 0.4%for the black spots.NOTE1It has been found(4)that all the round spots on the originalchart,except the following,are correct within 2%or 0.005 mm2(whateveris the larger).For especial accuracy,the designated areas in squaremillimeters of the following round spots should be changed to those givenin parentheses:1.00(1.08),0.80(0.76),0.60(0.58),0.40(0.42),0.30(0.31),0.25(0.26),0.20(0.21),0.15(0.16),0.10(0.11),0.9(0.10).Onlythe round spots are used for the analysis.In examining an actual TAPPI Standard Dirt Chart,it will be noted thatnone of the rectangles stand out nearly so well as do the round dots havingthe same area.In fact,if examined with a reading glass held out of focus,with the particular shape of rectangles used in that chart,it will be seenthat their equivalent black area is only about two thirds that of the rounddots of the same actual area.Furthermore,in the actual photographic1This 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 1962.Last previous edition approved in 1993 as D 2019 93.2The boldface numbers in parentheses refer to the