photoengraving | printing - Encyclopedia Britannica

photoengraving, any of several processes for producing printing plates by photographic means. In general, a plate coated with a photosensitive substance is ... photoengraving TableofContents photoengraving IntroductionHistoryofphotoengravingEarlyetchedplatesWet-collodionphotographyThehalftoneprocessBasisforselectionofscreenrulingContactscreensThebendayprocessSpecialeffectsProcessdevelopmentsChemicaletching—traditionalandpowderlessprocessesElectromechanicalplatemakingColourscannersModernphotoengravingtechniquesBasicproductionprocessesCameraanddarkroomequipmentPlatecoatingandprintingEtchingandfinishingBlockingandproofingColourplateproductionColourseparationEliminationofmoiréElectromechanicalengravingmachines—colourscannersProductionspecificationsLineplatesHalftonespecificationsCombinationline-and-halftoneplatesEngravingtechniquesappliedtointaglioprocessesLineintaglioGravureandrotogravureOthermethods FastFacts 2-MinSummary RelatedContent Media Images More AdditionalReading MoreArticlesOnThisTopic Contributors ArticleHistory Home VisualArts GraphicArt photoengraving printing Actions Cite verifiedCite Whileeveryefforthasbeenmadetofollowcitationstylerules,theremaybesomediscrepancies. 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ExternalWebsites InternetArchive-"Amanualofphoto-engraving:containingpracticalinstructionsforproducingphoto-engravedplatesinrelief-lineandhalf-tonewithchaptersondryplatedevelopmentandhalf-tonecolorwork" Print print Print Pleaseselectwhichsectionsyouwouldliketoprint: TableOfContents Cite verifiedCite Whileeveryefforthasbeenmadetofollowcitationstylerules,theremaybesomediscrepancies. Pleaserefertotheappropriatestylemanualorothersourcesifyouhaveanyquestions. SelectCitationStyle MLA APA ChicagoManualofStyle CopyCitation Share Share Sharetosocialmedia Facebook Twitter URL https://www.britannica.com/technology/photoengraving More GiveFeedback ExternalWebsites Feedback Corrections?Updates?Omissions?Letusknowifyouhavesuggestionstoimprovethisarticle(requireslogin). 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ExternalWebsites InternetArchive-"Amanualofphoto-engraving:containingpracticalinstructionsforproducingphoto-engravedplatesinrelief-lineandhalf-tonewithchaptersondryplatedevelopmentandhalf-tonecolorwork" By PaulF.Borth • EditHistory TableofContents RelatedTopics: strippingfilm colourscanner carbontissue processcamera gallerycamera ...(Showmore) Seeallrelatedcontent→ photoengraving,anyofseveralprocessesforproducingprintingplatesbyphotographicmeans.Ingeneral,aplatecoatedwithaphotosensitivesubstanceisexposedtoanimage,usuallyonfilm;theplateisthentreatedinvariousways,dependinguponwhetheritistobeusedinarelief(letterpress)oranintaglio(gravure)printingprocess.Engravingisthebroadtermfortheprocedureusedinmakingplates,inwhichprintingandnonprintingareasaredistinguishedbytheirheightwithrespecttothegeneralplaneofthesurface,theartisticdecorationcreatedbymechanicallyincisingadesignintoasurface,andthecreationoforiginalworksofartbytoolingoretchinganimageintothemetal(orplastic)surfaceandtransferringtheresultantimagetopaper.Fordetailedinformationontheselasttwosubjects,seeprintmaking.Thisarticleislimitedtoconsiderationoftheprocedureswherebyaprintingsurfaceusefulintheproductionofmultipleink-on-paperimagesisproduced.Thetermphotoengravingiscorrectlyappliedtotheproceduresdiscussedhere,sincetheuseoflightenergy,asinvolvedinphotographicprocesses,isessential.Adistinctionmustbemadebetweenareliefprintingplate,inwhichtheink-carrying(orimage-bearing)surfacecoincideswiththegeneralleveloftheplatesurface,withnonimageportionscutbelowthesurface,andintaglioprintingsurfaces,inwhichtheink-carryingimageelementsareincisedintotheplatesurface.Inthefirsttypeofprinting,auniformfilmofinkisdistributedoverthesurfaceoftheplateandtransferredfromtheindividualimageelementstothereceivingpapersurface.Inthesecond,theplateisfloodedwithalow-viscosity(thin)ink,thenwipedwithablade(doctorblade)toremoveanyinkadheringtothesurface.Thedoctoringactionleavestheincisedintaglioimagefilledwithink;later,aspaperisbroughtintocontactwiththisimageandpressureisapplied,surface-tensionandcapillary-actionforcescausetheinktotransferfromtheplatetothepaper. Historyofphotoengraving Theearliestengravedprintingunitswerewoodengravings,inwhichthenonimageareasofanillustrationwereremovedbycarvingthemfromthesurfaceofaflatwoodblock.TheoldestknownillustrationprintedfromawoodenblockwasaBuddhistscrolldiscoveredin1866,inKorea.Whilethedatingoftheprintisnotexact,itisbelievedtohavebeenpreparedabout750ce.TheChineseDiamondSutra,dated868,incorporatesawoodcuttitlepageandtextthatincludesnumerouswoodcutimages. Fromthese8th-and9th-centurydates,itisclearthattheuseofwoodcuts(imagescutintoasurfaceparalleltothewoodgrain)andwood-blockengravings(imagesincisedintotheendgrainofanassembledblock)antedatestheinventionofmovabletype.TheearliestextantexampleofaEuropeanprintfromawoodengravingtowhichareliabledatemaybeattributedisaprinttitled“St.Christopher,”dated1423,discoveredinthelibraryoftheCarthusianmonasteryinBuxheim,Germany.Anotherauthenticatedexampleof15th-centurywood-blockprintingisthe“ApocalypseofSt.John,”printedin1450,aftera14th-centurymanuscript. Earlyetchedplates Platesengravedinwoodcontinuedtofinduseinprintingapplicationthroughthelate-medievalandearly-modernperiods.Platesmadeofcopper,pewter,andothermetalswerealsoproduced,byaprocessinwhichanimageinwaxorbitumenwasdrawnon,ortransferredto,thesurfaceoftheplateandnonimageareasremovedbyactionofappropriateacids. Preparationofintaglioprintingplatesbycoatingametalplatewithanetchant-resistantsubstance(ground)suchaswax,bitumen,orshellac,scratchingthroughthissubstance(ground)toexposetheplatesurface,thenetchinginacidsisalsoalate-medievalEuropeandevelopment.Thisprocess,however,developedasamediumofartisticexpression,ratherthanatechniqueforthemassproductionofprintedimages. Thefirstexperimentalapplicationoflight-sensitivematerialstotheproductionofprintingsurfaceswasmadebyJosephNicéphoreNiepce,ofFrance,anearlyresearcherinlithographywhobeganhisexperimentsinabout1813.Heiscreditedwithhavingproducedthefirstpermanentphotograph.In1826Niepcecoatedapewterorcopperplatewithaphotosensitiveasphaltumandexposedthesurfacetobrightsunlightthroughanetchingofaportrait,whichservedasapositiveimage.Sunlightpassingthroughthebackgroundoftheetchinghardenedtheasphaltum,whiletheprotectedareas,undertheinkedportionoftheetching,weredevelopedinoiloflavenderandwhitepetroleumtocreateanimageinexposedmetal.Thisimagewasthenetchedintotheplate,andfromtheintaglioimage,printsweremadeonacopperplatepress. Thoughthisbasicdiscoverywasofhistoricalimportance,itdidnotbringabouttheimmediateuseofphotoengravedimagesforprinting,andmanyotherattemptstoproduceengravingsbyexploitationofthephotosensitivityofvariousnaturalcompoundsweremadebyexperimentersinEuropeandtheUnitedStates.Theoriginofthemodernphotoengravingprocessrests,however,onthereport(1839)byaScottishscientistandinventor,MungoPonton,ofthelight-sensitivepropertiesofcertainchromiumcompounds.ButPonton,whodemonstratedthechemicalchangethatoccurswhengluecontainingacompoundofchromiumisacteduponbylight,wasnotconcernedwithpreparationofprintingplates,anditremainedforWilliamHenryFoxTalbot,anEnglishpioneerinphotography,toproposetheuseofchromium-treatedcolloidssuchasalbuminasanetchant-resistantforpreparationofintaglioprintingsurfaces. Early19th-centuryworkonproductionofchemicallyetchedletterpressprintingplatesantedated,inmanyinstances,theinventionofphotography.AresearcherinParisdevelopedaprocessforthepreparationofengravingsonzinc.Hisworkinvolvedtransferofanimagetothezincplatebymechanicalmeans,usinginkorwax,andtheremovalofthenonprintingareasinaseriesofetchingoperations,eachofwhichinvolvedapplyingacoatingofinktothesidewallsoftheetchedlinesbymeansofresilientrollers.Theinkservedtoprotectthelinesoftheengravingfromtheactionoftheetchingacid,sothattheprintingareawasnotreduced. LoadNextPage