Moire

Introduction

Moireisataintedinterferencemeshcausedbyoverlappingandconflictingdatagrids.Moireusuallyoccursinthethreestagesofimageprocessing.1.Scanningofhighlydetailedtextures:Forexample,whenscanningimagesontexturedfabrics,moirepatternswillbegenerated,whicharecausedbythescanneritself.Thescannerisnotsensitiveenoughtothedetailsthatitreads,andthemoirégeneratedispresentinthescannedimageandcanhardlyberemoved.

2.Outputincorrectscreenangle:Whenmulti-colorimagesareoutputatthewrongscreenangle,moirepatternswillappearontheimageprintedontheprinter.Inaddition,ifthescreenangledoesnotusetheoptimalvalue,moiréwillinevitablyappear.

3.Scanningpre-screenedimages:Whenscanningimagesthathavebeenprinted,thecontinuousadjustmentinformationonphotosortransparenciesisnotscanned,butthescreensareadjusted.Thescannerpartiallyrecognizesthespacebetweenthedots,butcannotcopyitasitisorconvertittoacontinuoustone.Asaresult,theimagecontainsmoiré.Inthiscase,severaltechniquescanbeusedtoreduceoreliminatemoiré.

One.Usetherotatingmethodtoeliminatethemoiré.Whenscanningaprescreenedcolorimage,themoirédoesnotonlyappearinonechannel(black),butmayappearinoneormorecolorchannels.Over-adjustingtheentireimagewillhaveanirreparableeffectontheinformationinthechannelthatdoesnotcontainpatternsatthebeginning.Whenscanning,theimageisnotplacedatarightangletothescanningplatform,butplacedatacertainotherangle.Thiscanforcethescannertodistortthemoreobviouscomponentcolors,suchascyanandblack,andwhenrotatingtheimageinPhotoshop,theedgeofthedotshapecanbeblurredduringtheinterpolationprocess,resultinginamorecontinuoustoneeffect.

Generallyscanat15°,30°or45°.Afterscanningtheimage,therearetwowaystorotatethescannedimage.

OneistoselectImage\RotateCanvas\Arbitrary(image\rotatecanvas\arbitraryangle),entertheangleoftheimagetoberotated,andthencutouttheextracanvasgeneratedafterrotatingtheentireimage;

2.Basicstepstoeliminatemoirébyblurring:

1.Scantheimageattwicethenormalresolutionminus10pixels.Inthisway,whenthefirstroundofblurfilterisapplied,theimagecontainsmoreinformationthanthestandardscan,whichwillcauselessdamagetoimportantdetails.Moreover,whentheresolutionoftheblurredimageisreducedinthefuture,moreconflictingdotstructuresmaybeeliminated.2.Blurtheimage.WhenopeningthescannedimageinPhotoshop,useaGaussianblurfiltertoslightlydistorttheshapeofthedots.Generallycloseto0.7pixelscandowell.3.Verifythecolorchannel.Inmanycases,themoiréonlyaffectsoneortwochannels,clickonthecolorchannelintheChannelspaneltocheckit.Afterfindingtheproblematiccolorchannel,applytheGaussianblurordespecklefilteragainusingtheabovemethodtofindouttheabnormaldotvalues​​andaveragethem.

4.Reducetheresolution.Afterblurringtheimage,reducetheimageresolutiontothedesiredvalue.SelectImage\ImageSize,selectConstrainProportionsandResampleImageoptions,andenteranewvalueintheresolutionfield.WhenPhotoshopinterpolatesatthenewresolution,itmustrecalculatethevalueofeachpixel,whichfurtherremovestheamountofmoiré.Ifthereisstillaslightpattern,checkthecolorchannelagain,anddoanotherGaussianblurwithasmallervalue(0.3-0.5pixels).

5.Sharpentheimage.Whenapplyingavignettemaskfiltertoadescreeningfilter,youmuststrikeabalancebetweenemphasizingthedetailsoftheimageandexaggeratingthemoiréthatisnoteasytoremove.Whenpreviewingtheeffectofthefilter,setthenumbervaluesothatthetexturebeginstostandoutThepreviousvalue.

Screenprinting

Moirépatternoftonescreenprinting

Overview

ScreenprintingLikeflatprintingandtypeprinting,dotsareusedtoreproducethetoneoftheoriginalmanuscript.ThedotsofY,M,C,Kcolorplatesinterferewitheachotherduringprinting,andvariousinterferencepatternsandpatternswillchangewiththesizeofthedotangledifference.Allpatternswillappearwithintheangleof45°,andrepeatwithintherangeof90°.Dotmoiréiscausedbyunevendensitydistributioncausedbyunevenarrangementofdotsintwoormorecolorsduringprinting.Thisunevendistributionisbetweencompletelyheavyandcompletelyjuxtaposeddots.Obviously,thedensityofheavydotsislessthanthedensityofparalleldots.Ifthedensitydifferenceistoolargeandalternatelyandregularly,moirepatternsappear.Inpractice,inordertoavoidtheoccurrenceofmoiré,theanglebetweenthecolorplatesofoffsetprintingandembossingfour-colorprintingshouldbegreaterthan22.5°.Generally,thedotanglesofyellow,magenta,cyan,andblackarearrangedat90°,15°,75.°,45°,sothatonlytheincludedanglebetweentheyellowplateandothercolorplatesislessthan22.5°,buttheyellowislighterandtheformationofmoireisnotveryobvious.

Sincethesilkscreenwovenstructureofthesilkscreenisalsoarrangedregularlyasthedots,thereisthepossibilityofmoirépatternsbetweenthesilkscreenandthefilm.Inaddition,thescreenprintinghasmorevariablefactorsthanoffsetprinting,sothemoirécontrolofgradationscreenprintingismorecomplicated.Thisarticlewillanalyzethereasonsforthemoiréproducedbythegradationsilkscreenanddiscussthemethodsofcontrollingmoiré.

Moirepatternoftheoriginalmanuscript

Whenshootingsomemanuscriptsofobjectsthatchangeregularly,therewillbemoirepatternsintheoriginalmanuscript,suchasfabricpatterns,wickerfurniture,fences,andshutters.Wait.Inaddition,theprintedmanuscriptwillhavemoireafterscanning.

Fortheoriginalmoiré,youmustfirstbeawarethatthemoiréwillbemoreobviousafterscreenprinting.Pleasetellthecustomerfirst

tobeclear,trytofindawaytoreplacethemanuscript,orproperlyblurtheseareaswhenprintingcolorseparationprocessing;andforprintedmanuscripts,youmustgotothescreenwhenscanning,Toremoveallthemoirépatterns,ofcourse,thisisattheexpenseoftheclarityoftheoriginalmanuscript.

Themoirépatternofthefilmitself

Duetotheuseofelectroniccolorseparationmachineordesktopprepresssystemimagetypesettingmachineforlaserscreening,theedgeofthedotisnotsmooth.Thefinerthedot,themoreThehighertheedgegreenroughness,thegreatertheprobabilityofmoireinthehighlightareaof​​theimage.Theedgesoftraditionaldotsareverysmooth,whiletheedgesoftheelectronicscreeningoftheelectricalextensionandthePostScriptdotsoftheimagesetterarenotsmooth.Theyarerelatedtotheresolutionoftheimagesetter,becausetheirscreeningmethodistousethelaserbeam"on"or"off"toexpose.Whena16x16dotmatrixlaserisusedtogenerateadot,thedotsareverydifferent.Obviously,theycannotbeassmoothastraditionalphotographicdotsanyway.

Moirepatternscausedbyscreens

Thestandardoffsetprintingscreenanglesare:yellow0°or90°,magenta15°,blue75°,black45°.Thedifficultiesfacedbyscreenprintingare:0°,90°,and45°arethebasicanglesformoire.Sincethenetworkcablesarefixedinonedirection,thescreennetworkcableswilldirectlyblockthetransparencyofthedotsthatblockthelines.AsshowninFigure5,theimageofthescreenat45°isatthebasiccrossingpointsduetothecrossedfibers.Topreventtheformationofdots,thehalftoneimagegeneratedbythiscorneristhemostpronetomoire.Figure6isthecommonmoireshapeproducedbythewiremesh.Themoirépatternproducedbythescreenisrelatedtothesizeofthedotsandthenumberofscreenmeshes.Thefinerthedots,themoreimportantthescreenangleofthecolorseparationfilmimage.Theratioofthemeshtothescreenline(screenmeshline/filmplusmeshline=mesh)Theratioofmeshtowire,suchas355mesh/100Lpi=3.55.)Thelargerthewireangle,thelessimportantthewireangle.Iftheratioislessthan4.0,theangleofthecolorseparationfilmusedwillbechanged.Themethodofchangeistoproduceachangeof±4-8°onthebasisoftheoffsetscreenangle.Themoirécausedbytheangleeffectoftenappearsinacertainarea,forahighmesh/dotratio.Themoiréwillbeinthehigh-profileareafirst,andastheratioofmesh/dotdecreases,themoiréwillcovertheentiretone.

Moireanti-counterfeiting

Applicationofmoireanti-counterfeitingtechnologyinprinting

Overview

HowtoAvoidingmoiréinprintingisaproblemthatresearchersandprintersareveryconcernedabout.Thisproblemhasalsocontributedtothedevelopmentandapplicationoffrequencymodulationtechnology.However,inadditiontoavoidingitsnegativeeffects,cantheexistenceofanythingmakethebestuseofit?Isitreallyuselessforthis"hateful"patternthataffectsprintingqualityandlookandfeel?Whetheritcanbeusedeffectively,itmaybeabletoplayacertainvaluewithoutbeinghatedbypeople.Atthistime,whatwethinkofistousethisfrequently-appearingandficklemoirepatterninthefieldofanti-counterfeiting.Ifthistechnologycanbesuccessfullyandeffectivelyapplied,itisforeseeablethatthistechnologywillbeasimpleandeconomicalanti-counterfeitingmethod.

Advantagesofmoireanti-counterfeiting

Intheprocessofmakingproductsnon-reproducibleandimitative,theapplicationandproductionofspecialpaper,specialink,specialprintingandotherspecialprocessesTherequiredtechnology,equipmentandcapitalinvestmentvary.

Inthenormalprintingconditionsandprocess,themoiréproducedbytheplate-makingtechnologyisusedtoachievetheeffectthatisdifficulttoimitate.Theadvantageofthisapproachis:intermsofproductioncosts,duetotheuseofconventionalprintingmethods,whetheritispaper,inkorprintingmachineryandotherprintingelements,theexistingconventionalmodelsandequipmentoftheprintingorganizationcanbeused,thuseliminatingtheneedtointroducespecialThecostofcapitalinvestment,technicalmaintenanceandhumanresourcesforequipmentorincreasingspecialprocessesismoreeconomicalandpractical.Intermsofeffectiveness,theprocessissimpletoproducedifferentchangesinthemoirepatternbysettingtheparametersofthemoirepattern,butitsregularityismoredifficulttograsp.Itslow-endimitationsuchasscanning,colorcopyingandothermeans,itseffectisdifficultItisunreal,soitismorereliableandeffective.

Fromtheperspectiveofapplicability,theuseofmoireanti-counterfeitingcanbeprintedintoproductanti-counterfeitingmarksordirectlyusedonproductaccessoriessuchasproductdescriptions.Itisbeautifulandobvious,andcanbecombinedwithotheranti-counterfeitingtechnologiesforawiderangeofuses.Comparedwithotherprintingmethods,theseadvantageshighlightthesuperiorityofitscostperformance.

Therealizationofmoireanti-counterfeiting

Howtousemoirétoachieveanti-counterfeitingeffectwithoutdestroyingthemainpartofthedesignimage?Thisinvolvestheapplicationofspotcoloreditions.Inpackagingprinting,itisoftennecessarytoprintaspotcolortoacolorspecifiedbyacertaincompany.Thisrequiresthatthiscolorfeatureareabeexpressedintheformofaspotcolorchannelduringthedesignandproductionprocess.Inthesubsequentcolorseparationandscreening,thespotcolorchannelisprocessedintothefifthfilmafterCMYK.AfterprintingtheCMYK,printthedeployedspotcolorink.

Theapplicationofmoirépatternsissimilartothisprocess.Thebackgroundoftheimagecanbeprocessedinthespotcolorchannel.Whenaddingthescreen,setdifferentdotparameters(screenangle,screenlinenumber,etc.),sothatthisanglecanformamoirépatternwithoneofthefourcolorstoobtainthefifthfilm.Thesettingofthescreenanglevalueonthisfilmisspecialandsubtle.Themoiréformedbetweenthisfilmandacertaincolorplateinthefour-colorfilmwillshowobviousdifferencesduetosubtlenumericalchanges.

Inaddition,ifimitatorswanttoscanorcopyandwaituntilthemethodisdifficulttofakeit,thisisbecausethemoiréiscomposedofdots,whichmustbeextremelysmall,andcopyingandscanningwillLeadtotheexpansionandblurringofoutlets.Ifthescreenisaddedagainonthebasisofthescannedmanuscript,therewillinevitablybeobviousdifferencesbetweentheprintedmatterandtheoriginal,anditwillbedifficulttoachievetheeffectofimitation.Atthesametime,inordertoincreaseitsreliability,youcanalsocombinethemoirépatternwithotheranti-counterfeitingmethods,suchasusingrandompatternsonthebackgroundtoincreasecomplexity;usinganti-counterfeitinginktoprintmoiréplates;usingspecialpaper(suchaswatermarkedpaper))Asabasisforprinting,etc.

Plate-makingtechniques

Plate-makingtechniquestoreducemoire

Stretchthenet

InordertofacilitateprintingandprintingForprintingpositioning,trytomakethescreeningandseparationfilmparallel(vertical)tothescreenframe,andchoosetosetthedotlineandscreenlineofeachcolorbasetothemostsuitableanglewiththesmallestmoire.Theoperationmethodis:firststretchthenettotherequiredtensiononthestretcher,andthenstickthemedicatedfilmofeachcolorseparationfilmfacedownonthescreen,underthelight,rotatethefilmuntilthetortoisebetweenthetwoThepositionwherethepatternisthesmallest,orwhenthemoirépatternisnotproduced,isthebestpositionoftheimageonthescreen.Anduseapentomarkthisbestpositiononthesilkscreen,asthepositioningoftheimagewhenprinting.Thenstickthescreenparallel(vertically)atthisposition,dry,andunloadthescreen,andmarkthecolornumberofthecolorseparationplateonthenetworktomakeaone-colorscreen.Theothercolorplatesarealsocarriedoutaccordingtothisoperation.Note:①Whenmakingthescreen,thecolorseparationfilmmustbeconsistentwiththepositionsetwhenthescreenisstretched;②Thetensiondifferenceofeachcolorseparationscreenisnotmorethan1N/cm;③Thethicknessofthephotosensitiveglueoneachscreenisthesame,Thesurfaceissmooth.

Anothermethodistofirsttakeastretchedscreen(0°or90°),findthebestpositionsofthefourcolorseparationfilmsonthisscreen,andpressthecolorseparationfilmRecordtheanglewiththescreenframerespectively,andthenstretchthescreenaccordingtothesamemeshnumber,tensionandangle,andthensticktothescreenframeaccordingtotherecordedposition,dry,unloadthescreen,andmakethescreen.Itshouldbefine-tunedduringprintingtomaketheeffectbetter.

Platemakingcontrol

ThescreenforprintinghalftoneimagesrequiresalowRZvalueofthephotosensitiveadhesiveandhighedgesharpness(smooth).Otherwise,moiréiseasytoappear,sointheproductionThequalityofcoatingorpastingshouldbecontrolledwhenprintingplates.

(1)Thethicknessofthephotosensitiveadhesivelayeronthescreenshouldbecontrolledatabout8μmhigherthanthescreen(dependingonthecharacteristicsoftheink).

(2)Afterapplyingphotosensitiveglueorattachingacapillaryphotosensitivefilm,thescreenshouldbedriedwiththeprintingsidefacingdown.Ifthephotosensitiveglueisusedtomaketheplate,thelasttimetheglueisappliedshouldfallontheprintingsurface.ConducivetoreducetheRZvalue.Eachtimethephotosensitiveglueisappliedtotheprintingsurface,theRZvalueisreducedby50%comparedtothepreviousone.Ifthephotosensitivelayeronthescreenstencilisverythin,theRZvaluewillbelarge,whichwillcauseunevenedgesofthedotsandincreasethepossibilityofmoiré.

(3)Inordertoimprovetheedgesharpnessofthedots,intheplatemakingmethod,theindirectplatemakingmethodshouldbethefirstchoice,followedbythephotosensitivefilm,andtrynottomaketheplatewithphotosensitiveglueasmuchaspossible.