Introduction
Sensitivematerialsarethegeneraltermformaterialssuchasfilm,filmandphotopaperusedinphotography.Photosensitivematerialsaregenerallydividedintotwocategories:blackandwhitephotosensitivematerialsandcolorphotosensitivematerials.Variousmaterialsusedinthefieldsoflighting,filmandtelevisionfilming,andprintingandplatemakingcanundergophotochemicalchangesundertheactionoflighttomeettherequirementsofuse.Dividedintotwocategories:silversaltphotosensitivematerialsandnon-silversaltphotosensitivematerials.Itscharacteristicisthatitisinsulativewhenthereisnolight,anditisconductivewhenthereislight.Theworkingprincipleofthecopiermakesuseofthischaracteristic.Inthecopier,thephotosensitivematerialiscoatedonthebasetomaketheprintingplate(printdrum)neededforcopying,sotheprintingplateisalsocalledthephotosensitiveplate(photosensitivedrum),whichisthecopierThebasiccorecomponents.Commonlyusedphotosensitivematerialsoncopiersincludeselenium,zincoxide,cadmiumsulfide,organicphotoconductor,etc.,whichareallidealphotoconductivematerials.
Classification
Therearemanyvarietiesofphotosensitivematerials,whicharegenerallyclassifiedaccordingtotheiruse,supportandcolorsensitivity:
Classificationaccordingtotheiruse
Accordingtotheuseofphotosensitivematerials,itcanbedividedintonegativephotosensitivematerials,positivephotosensitivematerialsandreversephotosensitivematerials.
1.Negativelight-sensitivematerials
Negativelight-sensitivematerialsarephotosensitivematerialsthataredirectlyusedtoshootscenes.Theimageobtainedafterexposureanddevelopmentofthisphotosensitivematerialisoppositetothelightanddarkimageofthescene.Itisusedasa"negativefilm"forcopyingthepositiveimage,suchasfilmnegatives,commonlyused120and135filmrolls,andphotocopiesofvariousprintingplates.
2.Positivephotosensitivematerial
Positivephotosensitivematerialisaphotosensitivematerialusedfortheduplicationandprintingofvariousnegativefilms.Thisphotosensitivematerialisincontactwiththenegativefilm(negativefilm)Ornegativeimageprojectionexposureanddevelopmentprocessing,theimageobtainedisthesameasthelightanddarksceneofthesubject,suchasvarioustypesofphotographicpaper,filmcopies,slides,etc.
3.Reversalphotosensitivematerial
Reversalphotosensitivematerialisaphotosensitivematerialwhoseimageobtainedafterphotographicexposureandreversaldevelopmentisthesameasthelightanddarksceneofthesubject.Itcannotonlytakenegativefilmasanegativelight-sensitivematerial,butalsocandirectlyobtainpositivefilmthroughreversaldevelopmentprocess,thuseliminatingtheneedforfilmcopyingprocess,sothatitcanbecopiedintothesamereversefilmastheimageofthenegativefilm,anditiscalledreversereversefilm.Negativefilm(orintermediatefilm,etc.).
Classificationbysupport
1.Dryplateisaphotosensitivematerialwithflatthinglassasasupport.Thiskindofphotosensitivematerialhasthecharacteristicsofflatnessandgoodrigidity,soitsimagedeformation(shrinkage)isverysmallafterdevelopmentprocessing,whichisverysuitableforprintingplateswithhighprecisionandphotosensitivematerialsforphotographysuchasphotogrammetry.Thedisadvantageisthatitisbulky,fragile,andunsuitableforcontinuousshooting.
2.Film
Filmisaphotosensitivematerialwithacolorlesstransparentorganicfilm(polyesterfilm)asasupport.Thedeformationofthisphotosensitivematerialisalsoverysmall,andbecauseithastheadvantagesoflightweight,curlingandnon-combustibility,itcanbemadeintoaphotosensitivematerialthatistensofmeterslongandrolledintoadisc.Itiswidelyusedinfilmproductionandordinaryphotography,andiscurrentlythemostused.Photosensitivematerial.
3.Photopaper
Photopaperisaphotosensitivematerialwithaglossywhitebariumsulfatepaperbaseasasupport.Suchasvariousprintingpapers,magnifyingpapers,oscillometricrecordingpapers,etc.;itisaphotosensitivematerialtoobtainapositiveimage,anditsconsumptionisalsoquitelarge.
Classifiedbycolorsensitivity
Becauseofthedifferentsensitivityofdifferentphotosensitiveemulsionstoeachspectralrange,photosensitivematerialscanbedividedintocolorblindfilm,positivecolorfilm,Panchromaticfilm,infraredfilmandcolorfilm,etc.
1.Colorblindfilm
Colorblindfilm(alsoknownascolorblindfilm)isaphotosensitivematerialmadeofsilverbromideemulsionthathasnotbeenopticallysensitized.Itisonlysensitivetoblueandpurplelight,andthesensitivityrangeis350-500nanometers(mμ).Allkindsofblack-and-whiteprintingpapers,magnifyingpapersandnegativephotosensitivematerialsusedinblack-and-whiteprintingbelongtocolorblindfilms.
2.Positivecolorfilm
Positivecolorfilmisaphotosensitivematerialmadebyaddingakindofpositivecolorsensitizertotheblindcoloremulsion.Itssensitivityrangeis350-580nanometers,thatis,itissensitivetoyellow,green,cyan,blue,andpurplelight,butithasaweakerperceptionofgreenlightanddoesnotperceiveredlight.
3.Panchromaticfilm
Thepanchromaticfilmisaphotosensitivematerialmadebyaddingoneorseveralsensitizerstotheblindcoloremulsion.Itssensitivityrangeis350-660nanometers,anditcanfeelallvisiblelight,butithasaweakperceptionofgreenlight.
4.Infraredfilm
Infraredfilmisaphotosensitivematerialmadebyaddinghumansensitizersandinfraredsensitizerstotheblindcoloremulsion.Itsphotosensitiverangeis350-1200nanometers,whichobviouslyincludestheinfraredbandrange.Thisphotosensitivematerialissuitableforshootingsceneswithverylowbrightness.
5.Colorfilm
Colorfilmismadebyaddingdifferentcolorcouplerstoblindcoloremulsion,orthochromaticemulsionandfullcoloremulsionandthencoatingthemonthesamefilmbaseinacertainorder.Madeofphotosensitivematerial.Thiskindofphotosensitivematerialcanfeelallvisiblelight,andaftercolordevelopmentprocessing,acolorimageisobtained.
Commonlyusedmaterials
Thephotosensitivematerialsoftenusedinphotostudiosmainlyincludephotosensitivefilmandphotosensitivepaper.Photosensitivefilmiscommonlyreferredtoassoftfilm(film),loosepagesarecalledperforatedsheets,androll-shapedonesarecalledfilm.Sensitivepaperisphotographicpaper,includingprintingpaperandmagnifyingpaper.Bothphotosensitivefilmandphotosensitivepaperarecomposedofmultiplelayersofmaterial.
Sensitivefilm
Thephotosensitivefilmiscomposedofaprotectivelayer,anemulsionlayer,abottomlayer,abaseandananti-halationlayer.
(1)Protectivelayer:Agelatinfilmiscoatedontheemulsion,thepurposeistoavoiddirectcontactbetweentheemulsionlayerandtheoutsideworld,andpreventtheemulsionlayerfrombeingrubbedandcausingfriction,fog,blackstreaks,andfrictionwires.Itprotectstheemulsionlayer.
(2)Emulsionlayer:Theemulsionlayerisalsocalledthephotosensitivelayer,commonlyknownasYaoying.Itisthemaincomponentofthephotosensitivematerial,whichisuniformlycoatedonthefilmbaseafterbeingmixedandmaturedbysilversaltandgelatin.Theemulsionlayerisdividedintoanupperemulsionlayerandaloweremulsionlayer.Thedifferenceisthattheupperemulsionlayerhashighsensitivityandlowgamma,whiletheloweremulsionlayeristheopposite,withlowsensitivityandhighgamma.Inthisway,thesensitivityofthefilmcanberelativelyincreased,thegrainsizeofthesilversaltcanbereduced,andtheexposurelatitudecanbeimproved.
(3)Thebottomlayer,thebottomlayeristhecombinedfilmoftheemulsionlayerandthefilmbase.Alayerofgelatinisappliedbetweentheemulsionlayerandthefilmbasetomaketheemulsionlayerfirmlyadheretothefilmbase.
(4)Filmbase:Thefilmbaseisthesupportofthefilm.Althoughemulsionisthemainmaterialforimageformationandoccupiesamajorpositioninfilm,itcannotbeusedduetolackofsufficientmechanicalstrength.Onlywhenitisadheredtothefilmbasecanithaveusevalue.Thefilmbaseitselfrequiresgoodtransparency,goodtoughnessandcertainphysicalandmechanicalstrength.Thebaseisgenerallymadeofcellulosetriacetate.Thiskindoffilmbasehasafirepointsimilartothatofordinarypaper,andiscalledasecurityfilmbase.
Therearestillsomefilmsinusenow,whichareresistanttolowtemperature,notbrittle,smallshrinkage,stablegeometricdimensions,highmechanicalstrength,thinfilmbase,andlightweight.Thisistheuseofpolyester(alsocalledpolyester),polycarbonateandothernewmaterialsmadeoffilmbase.
(5)Anti-halationlayer:Theanti-halationlayerisunderthebase,whichisthelowestlayerofthephotosensitivematerial.Itsfunctionistopreventthephotosensitivematerialfromproducinghaloandlightpenetrationintheexposurearea,sothatthelayercanabsorbthescatteredlightanddirectlighttransmittedthroughtheemulsionlayerandthefilmbasetothegreatestextent,soastopreventthereflectionandrefractionofthelightfromcausinghalo.Theresolutionofthebowisreducedandthesharpnessisweakened,whichseriouslyaffectsthepicturequality.Generally,theanti-halationlayerofblackself-negativefilmusescarbonblack(acetylenecarbonblack),whichisdispersedingelatinandcoatedonthebackofthefilmbase.Inadditiontoitsanti-halationproperties,italsohasananti-curleffect.
Sensitivepaper
Thestructureofblack-and-whitephotosensitivepaper(ie,photographicpaper)issimplerthanblack-and-whitefilmfromthecross-section,butitisalsocomposedofmultiplelayersofmaterials,usuallywithaprotectivelayer,Emulsionlayer,bariumbottomlayer,paperbase.
(1)Protectivelayer:Theprotectivelayerofphotosensitivepaperisalsogelatin,anditsfunctionisthesameasthatofphotosensitivefilm.
(2)Emulsionlayer:Theemulsionlayeristhemaincomponentofphotographicpaper.Itisevenlycoatedonthepaperbaseafterbeingmaturedwithsilversaltandgelatin.Thesilversaltcrystalsintheemulsionlayerofphotosensitivepaperaresmallerthanthesilversaltcrystalsintheemulsionlayerofthephotosensitivefilm,especiallythesilversaltcrystalsinthephotographicpaperaresmaller,andtheemulsionlayerisalsorelativelythin.Generally,itdoesnotcontainpigments.Onlythecolorsensitivityofthesilversaltitselfisenough..
(3)Paperbase:Thepaperbaseisthesupportofthephotographicpaper,anditsfunctionisthesameasthatofthefilmbase.Becausethephotographisobservedbyreflectedlight,theemulsionlayerofthephotographicpaperiscoatedonthepaperbase.Therawmaterialofcommonlyusedphotosensitivepaperisflaxorcottonfiber.Therequirementsforthepaperbasearerelativelyhigh.Itrequiresgoodwaterresistance,highwetstrength,acidandalkaliresistanceduringprocessing,nolooseness,nohair,foaming,andelasticity.Small,noteasytodeformafterdrying.Thecolorofthepaperbaseiswhite,withlessdustandmetalspots,otherwiseblackandwhitespotswillappearonthephotopaper,whichwillaffecttheuse.
(4)Bariumbottomlayer:Alayerofbariumsulfateiscoatedbetweenthepaperbaseofthephotosensitivepaperandtheemulsionlayer.Thisisthebariumbottomlayer.Itsfunctionistofilltheporesonthepaperbaseandcoversomeoftheshortcomingsofthepapersurface;theotheristoisolatetheimpuritiesinthepaperbasesothatitdoesnotreactchemicallywiththeemulsion;andthethirdistoincreasetheadhesionbetweentheemulsionandthepaperbase.Nodelaminationandseparation.Fourth,changethepaperpatternandincreasethevarietyofphotographicphotosensitivepaper.
Precautions
Storage
Sensitivematerialsshouldbesealedandstoredinaclosed,dryanddarkplace,awayfromdirectsunlight.Needtoavoidhightemperatureandhighhumidity.Evenifthereisapackage,avoiddirectsunlight.Theunpackedandexpiredonesshouldbeusedupassoonaspossible.Don'ttrytoopentheundevelopedfilmandpaper,youwillregretit.
Toxicityandsafety
Photochromicmaterialsareslightlyirritatingtotherespiratorytractforskin.Theyshouldbesealedwhentransported,andtheenvironmentduringprintingoperationsshouldbewellventilated.Aftertheinkiscompletelydried,therewillnotbeanypeculiarsmellorirritation,whichmeetsthestandardsofsafetoysandfoodpackagingspecifications.
DeadpixelsofCCDandrepairissues
Whenshootingnightscenesorwhenthelenscoveriscoveredforalongtimeexposure,thecolorpointsontheimagearenotnecessarilyallCCDpixels,somearenoise.AftertheCCDtemperatureislowered,itwillbeimproved,andsomecanalsobeimprovedthroughfirmwareupgrade.
IftheCCDreallyhasbadpixels,itcanbesaidthatitcannotberepaired,becauseitisahardwareproblemoftheCCD.ItisalmostimpossibletorepairacertainimagingunitoftheCCD,anditisnoteconomical.ChangethecameraorchangetheCCD.
LiveMOSphotosensitivedevicescanbecomparabletofullframe(FFT)CCDintermsofpicturequality,andcomparabletoCMOSintermsoflowpowerconsumption.
Thesimplifiedcircuitshortensthedistancefromthephotodiodetothemicrolens,thusensuringexcellentsensitivityandimagequalitywithalargeincidentangle.
1.Resolution:7.5MP,withexcellentlow-lightperformancecharacteristics;
2.Gain:Lownoisetechnologyisusedtoreducegranularity;
3.Modulationrange:simplifiestheregisterandothercircuits,makestheFFT-CCDphotosensitivediodehasalargerphotosensitivearea,improvesthesensitivityandimprovestheresponsespeed;
4,lowpowerconsumption:itsfunctionTheconsumptionisabouthalfofFFT-CCD;
5.Highspeed:Thesimplecircuitstructureimprovestheoverallprocessingspeed.
Materialapplication
1.Dryingmethod:(self-drying,baking-drying,UVcuring),itcanbedilutedwithcorrespondingthinnerwhenusing.(Water-basedinkcanalsobecustomizedanddilutedwithwater)Itisrecommendedtousewhiteorlightwhiteastheprintingbackground,whichcanincreasethedegreeofdifferenceincolorchanges.
2.Ifscreenprintingisrequired:selectthemeshsizebetween150meshand200mesh.
3.Applicablesubstrate:screenprinting\offsetprinting\transferprinting\padprinting\spraying,etc.,paper/cloth/metal/glass/ceramic/plastic).