1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS ISO 18908:2000 ICS 37.
2、040.20 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Imaging materials Photographic film Determination of folding enduranceThis British Standard, having been prepared under the direction of the Consumer Products and Services Sector Committee, was published under the authorit
3、y of the Standards Committee and comes into effect on 15 July 2000 BSI 07-2000 ISBN 0 580 36014 8 BS ISO 18908:2000 Amendments issued since publication Amd. No. Date Comments National foreword This British Standard reproduces verbatim ISO 18908:2000 and implements it as the UK national standard. The
4、 UK participation in its preparation was entrusted to Technical Committee CPW/42, Photography, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the
5、 UK interests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publicati
6、ons referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisio
7、ns of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, the ISO title page, pages ii to v,
8、a blank page, pages 1 to 9 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued.Referencenumber ISO18908:2000(E) INTERNATIONAL STANDARD ISO 18908 Firstedition 2000-05-15 ImagingmaterialsPhotographicfilm Determinationoffoldingendurance Matr
9、iaux pour limage Films photographiques Dtermination de la rsistance au pliageISO18908:2000(E) ii ISO18908:2000(E)iii Contents Page Foreword.iv Introduction.v 1 Scope1 2 Termanddefinition.1 3 Principle1 4 Apparatus.1 5 Sampling.2 6 Conditioningandtestconditions.2 7 Procedure.3 8 Interpretationofresul
10、ts3 9 Testreport5 AnnexA(informative)NumberingsystemforrelatedInternationalStandards6 AnnexB(informative)DescriptionofpartsofMITfolding-endurancetester.8 Bibliography9ISO18908:2000(E) iv Foreword ISO(theInternationalOrganizationforStandardization)isaworldwidefederationofnationalstandardsbodies(ISO m
11、emberbodies).TheworkofpreparingInternationalStandardsisnormallycarriedoutthroughISOtechnical committees.Eachmemberbodyinterestedinasubjectforwhichatechnicalcommitteehasbeenestablishedhas therighttoberepresentedonthatcommittee.Internationalorganizations,governmentalandnon-governmental,in liaisonwithI
12、SO,alsotakepartinthework.ISOcollaboratescloselywiththeInternationalElectrotechnical Commission(IEC)onallmattersofelectrotechnicalstandardization. InternationalStandardsaredraftedinaccordancewiththerulesgivenintheISO/IECDirectives,Part3. DraftInternationalStandardsadoptedbythetechnicalcommitteesareci
13、rculatedtothememberbodiesforvoting. PublicationasanInternationalStandardrequiresapprovalbyatleast75%ofthememberbodiescastingavote. AttentionisdrawntothepossibilitythatsomeoftheelementsofthisInternationalStandardmaybethesubjectof patentrights.ISOshallnotbeheldresponsibleforidentifyinganyorallsuchpate
14、ntrights. InternationalStandardISO18908waspreparedbyTechnicalCommitteeISO/TC42, Photography. ThisfirsteditioncancelsandreplacesISO8776:1988,ofwhichitconstitutesaminorrevision. ThisInternationalStandardisoneofaseriesofstandardsdealingwiththephysicalpropertiesandstabilityof imagingmaterials.Tofacilita
15、teidentificationoftheseInternationalStandards,theyareassignedanumberwithin theblockfrom1890018999(seeannexA). AnnexesAandBofthisInternationalStandardareforinformationonly.ISO18908:2000(E)v Introduction Photographicfilmshouldhavesufficientfoldingendurancetopermitsatisfactoryperformancewhenusedinthe e
16、quipmentforwhichitisintendedundertheatmosphericconditionslikelytobeencounteredinpractice. Photographicfilmisessentiallyalaminateoftwoormoredifferentmaterials,generallyaplasticssupportandthe photosensitiveemulsion.Thelatterisusuallymadeofimageformingchemicalssuspendedingelatinoranother polymericbinde
17、r. Thefoldingenduranceofphotographicfilmisaffectedadverselybybothreducedtemperatureandreducedrelative humidity.Inmostapplications,foldingendurancelossatlowrelativehumidityisencounteredmorefrequentlythan lossatalowtemperature.Moreover,amarkedchangeinfilmflexibilitymayoccurwithonlyaverysmallchangein r
18、elativehumiditybelowalevelofabout25%.Thismeansthatfoldingendurancetestsonphotographicfilmshould becarriedoutonlyinanatmospherethatisaccuratelycontrolledwithrespecttobothtemperatureandrelative humidity. Thefoldingenduranceoffilmisverydependentonthesamplethicknessdecreasingwithanincreaseinthickness of
19、eitherthebaseortheemulsion.Forthisreason,thethicknessofthefilmlayershavetobeconsideredwhen comparingthebehaviourofdifferentfilms.Thetemperaturesandrelativehumiditiestowhichthefilmhasbeen subjectedbetweenmanufactureandtestingmayalsoaffectthefoldingenduranceeventhoughthesampleis reconditionedtoastanda
20、rdtemperatureandhumidity. Gelatinisgenerallymorebrittlethanfilmbase,sothatphotographicfilmhavingagelatinlayerononlyonesideis usuallymorebrittleifbentwiththegelatin-sideout(thatis,gelatinundertension).Thiscanaffectthefolding endurance,dependingonthedirectionofthefirstfold. Thefoldingenduranceofphotog
21、raphicfilmmayvaryindifferentdirectionsifthebaseisorientedmoreinone directionthananother.Thereisgenerallynodirectionaleffectintheemulsion. ThisInternationalStandardcoverstheMITfoldingendurancetestinwhichthefilmissubjectedtoarapidand repeatedfoldingactionuntilitbreaks. Differenttypesoffailureoccurwhen
22、filmisflexed.Failuremayconsistofveryfinecracksintheemulsion(without abreakinthesupport)whichareobjectionablewhenthephotographisviewed.Failuremayalsoconsistofcracks inthesupportoracompletebreak. Thewedgebrittlenesstest,standardizedinISO18907(see2inthebibliography),cangenerallydetectthe presenceofemul
23、sioncracksafterasingleflex.However,emulsioncracksarenotvisibleduringtheMITtest. Theymayoccurafterrelativelyfewflexesandresultinsubsequentflexingofonlythefilmbaseitselfwith consequenthigherfoldingendurance.Forthisreason,theMITfoldtestmaynotnecessarilybeinagreementwith ISO18907.Thetwotestsmayalsodisag
24、reebecausetheapparentbrittleness(orlackofflexibility)andfatigue resistancecanalsobedependentuponthemannerinwhichthephotographicfilmismechanicallytreatedwith respecttoboththedegreeandthespeedofstraining.Thereareanumberoffoldingendurancetestsinadditionto theMITfoldingendurancetest,asdescribedinISO5626
25、(see1inthebibliography). Filmsmayberated differentlyaccordingtothedifferenttests.INTERNATIONALSTANDARD ISO18908:2000(E)1 ImagingmaterialsPhotographicfilmDeterminationoffolding endurance 1 Scope ThisInternationalStandardspecifiesamethodfordeterminingandquantitativelyexpressingthefoldingendurance ofph
26、otographicfilm.ThemethodisbasedontheMITfolding-endurancetesterdescribedinannexB.Itisan analyticaltestandisnotintendedtosimulatepracticaluseconditions. ThisInternationalStandardisapplicabletofilmwithorwithoutagelatinbacking.Itmayalsobeappliedtoeither raworprocessedfilm,althoughtheflexibilitylevelofag
27、ivenfilmcanbequitedifferentafterprocessing. EquipmentsimilartothatdescribedinthisInternationalStandardmaybeusedprovidedthatacorrelationhasbeen establishedbetweentheresultsobtainedusingsuchequipmentandtheresultsobtainedusingtheequipment described. 2 Termanddefinition ForthepurposesofthisInternational
28、Standard,thefollowingtermanddefinitionapplies. 2.1 foldingendurance measureoffatigueresistanceaftermultipleflexing 3Principle Folding,backwardsandforwardsinastandardizedmanner,ofasampleoffilmsubjectedtoalongitudinalstress untilitbreaks. 4 Apparatus 4.1 Testchamber Anair-conditionedcabinetorwalk-inro
29、omshallbeusedforbothconditioningandtesting.Thetemperatureshall becontrolledtowithin 1 o C.Therelativehumidityshallbecontrolledtowithin 1%atrelativehumiditiesbelow 30%andtowithin 2%athigherhumidities.Thelinearairvelocityshallbeatleast150mm/s. Ifawalk-inconditionedroomisused,theairvelocityshallbeadequ
30、atetomaintaintheconditionsspecified.The numberofpersonnelpermittedintheroomduringtestingshallbelimitedandprecautionstakentopreventthe operatorsbreathreachingthefilm. 4.2 Testapparatus TheMITfolding-endurancetester(seeFigure1)shallholdthesampleinaverticalpositionunderapredetermined tensionbetweentwoc
31、lamps.TheupperclampisstationaryandthelowerclamposcillatesthroughanangleofISO18908:2000(E) 2 135 o 5 o toboththerightandleftoftheverticalposition. Thisoscillationisatafrequencyof175cycles 25cycles,ordoublefolds,perminute. Eachofthetwofoldingsurfaces,overwhichthesampleisbentinthelowerjaw,hasaradiusofc
32、urvatureof 0,38mm 0,03mm.Themachineisprovidedwithacountertoregisterthetotalnumberofdoublefoldsrequired tobreakthesample.ThepartsoftheapparatusaredescribedinmoredetailinannexB. 5 Sampling 5.1 Preparationofsamples Filmsamplesshallbecutinanatmosphereofapproximately23 o Cand50%relativehumidity. NOTE Ift
33、hesamplesarecutatlowrelativehumidities,itmaybedifficulttoobtainsmoothedges.Handlingunderthese conditionscanalsocauseemulsioncrackingwhichwillaffectthesubsequentfoldingendurance.Exposuretohighrelative humiditiescanpermanentlyalterthesubsequentbrittlenessbehaviourofthefilm Thesamplecuttershallbeofapre
34、cisiontypeandshallbekeptsharpsothatthesampleedgesaresmoothand freeofnicks.Rubberglovesshallbewornbytheoperatorwhenhandlingthesamples,bothintheirpreparation andtesting. NOTE Rubberglovesarespecifiedinordertoavoidmoisturetransferfromtheoperatortothesample. 5.2 Selectionofsamples Asetofatleast10samples
35、shallbepreparedforeachtest.Wherethefilmsizepermits,onesetofsamples shouldbecutinthemachinedirectionandasecondsetinthetransverse(cross)direction.Ifthefilmhasa discretebackinglayer,aseparatesetofsamplesshallbecutinatleastoneofthetwoprincipaldirectionsto enablethefilmtobetestedwithboththeemulsion-sidea
36、ndthereverse-sideintensiononthefirstfold. NOTE IntheMITfolding-endurancetester,thesamefilmcangivedifferentresultsdependingonthedirectionofthefirst fold. 5.3 Sizeofsamples Standardfilmsamplesshallbe120mmlongand15mmto16mmwide. 6 Conditioningandtestconditions 6.1 Conditioningofsamples Samplesshallbecon
37、ditionedinthetestchamber(4.1)untilpracticalmoistureequilibriumhasbeenreached.This maybedeterminedbyweighingthesamplesatregularintervalsanddeterminingthetimeatwhichfurther conditioningdoesnotappreciablychangetheweight.Inmanyinstancesthistimewillbeinthevicinityof4h,but actualtimeswillvaryduetoaccessof
38、theconditioningairandthetypeandthicknessofthematerial.The conditioningtimeshouldnotexceed24h. Filmshallbeheldinrackspermittingfreecirculationofairaroundthesamples. 6.2 Testconditions Therecommendedrelativehumidityfortestingshallbe15%whenthecontributionofanemulsionorbacking gelatinlayertofoldingendur
39、anceisofinterest.Arelativehumidityof50%ismoreusefulforevaluatingthe contributionofthesupport.ISO18908:2000(E)3 NOTE Thefoldingenduranceofpolyethyleneterephthalate(polyester)basefilmsissohighthatanMITfoldingendurance testisimpracticable. Thestandardtemperaturefortestingshallbe23 o C.However,othertemp
40、eraturesmaybeusedwheretheeffectof temperatureistobeinvestigated. Filmsamplesshallnotberemovedfromtheconditioningatmospherefortestingexceptattemperaturesof0 o Cor below.Fortestingfilmat0 o Corbelow,samplesshallbeconditionedatthedesiredrelativehumidityat23 o C, sealedinsmalltapedcans,cooledlongenought
41、oreachthetesttemperature,andthenremoved,oneatatime,for testing. NOTE Directcontrolofrelativehumidityattemperaturesof0 o Corbelowisimpracticable,butoncephotographicfilmis conditioned,therateofgainorlossofmoistureismuchloweratlowtemperatures. 7 Procedure Levelthetestapparatus(4.2)andturntheoscillating
42、foldingheadsothatthesampleslotisvertical.Placethefilm sampleinthemachinesothattheemulsionisintensiononthefirstfold(seethenotein6.2).Thedirectionin whichthelowerclampstartstorotatecanberegulatedbymanuallyturningtheknurledflywheelonthedriveshaft inthesamedirectionastheinstrumentoperates.Ifthefilmhasad
43、iscretebackinglayer,twotestsshallberun, onewiththeemulsionundertensiononthefirstfoldandonewiththebackingundertensiononthefirstfold.Adjust thetensiononthesampleto9,81N.Readthenumberoffoldsfromthecounterwhenthesamplebreaks. Perforatedfilmmaybetestedbypositioningthesampleinthejawssothatthefoldismadebet
44、weensuccessive perforations. 8 Interpretationofresults Forfilmsapproximately0,15mmthick,anaverageMITfolding-endurancevalueof20ormoredoublefolds indicatesareasonablyacceptablefilmattheconditionsunderwhichthetestwasmade.Avalueof3orless denotesaverybrittleorfatigue-pronefilm.Theserangesdifferforfilmswh
45、ichareeitherthickerorthinner.An averagedifferencebetweentwofilmsoflessthan3MITdoublefoldsisnotbelievedtobesignificant. Iftheadhesionbetweentheemulsion(orbacking)andthesupportisweak,separationmayoccurduringthe foldingtestatthebendingarea.Thismaybedeterminedbytestingadditionalsamplesandstoppingthemach
46、ine priortosamplebreakagetopermitvisualinspection.Whenthishappens,thetestisnotvalid.ISO18908:2000(E) 4 Key 1 Setscrewtolockupperclampatspecified tension 2Pivot 3 Counter 4 Uppersampleclamp 5 Sample 6 Centreofoscillation Radiusofcurvatureoftwofoldingsurfaces: 0,38mm 7 Lowersampleclamp 8 Oscillationof
47、foldingheadis135toboth rightandleftoftheverticalposition Figure1OperatingmechanismoftheMITfolding-endurancetesterISO18908:2000(E)5 9 Testreport Thetestreportshallincludethefollowinginformation: referencetothisInternationalStandard; averagenumberofdoublefoldsrequiredtobreakthesamplesineachmannerteste
48、d,forexample, lengthwise,widthwise,startedwithemulsionintension,orstartedwithbackingintension; temperatureandrelativehumidityduringthetest; averagethicknessofthebaseemulsionandbackinglayer.ISO18908:2000(E) 6 AnnexA (informative) NumberingsystemforrelatedInternationalStandards Thecurrentnumberingsyst
49、emforTC42documentsdealingwiththephysicalpropertiesandstabilityofimaging materialsisconfusingsincethefivedigitnumbersthatareusedarenotinanyconsecutiveorder.Tofacilitate rememberingthenumbers,ISOhassetasideablockofnumbersfrom18900to18999andallrevisionsandnew standardswillbegivenanumberwithinthisblock.ThelastthreedigitswillbeidenticaltothecurrentANSI/PIMA numbersofpublisheddocuments.ThiswillbeadvantageoustothetechnicalexpertsfromGermany,Japan,United KingdomandtheUSAwhohavepreparedthestandardandwhoarefamiliarwiththeANSI/PIMAnumbers. AsthepresentInter
