Download - Part II: Photo Editing

UCSDSchoolofMedicine,OfficeofEducationalComputing HeleneHoffman,PhD<[email protected]>

PhotoshopVersionPSCS3PartII:PhotoEditingM.E.D.S.Workshop,March2009

SectionI:BasicImageEditingProcess

1. Open2. Createcopyforediting3. Rotate4. Adjustbrightnessandcontrast5. Adjustcolorbalance6. Crop7. Resize8. Sharpen9. Save(forprint,email,web,etc)

SectionII:Techniquesthataddressspecificproblems/needs

1. Dust&Scratchesfilter2. CloneStamptool3. HealingBrushtool4. SpotHealingBrushtool5. BurnorDodgetool

SectionIII:Creativetechniqueswithfilters

WhatphotoeditingprogramshouldIuse?AdobePhotoshopistheleadinggraphicseditingprogramusedbyprofessionalsandseriousamateurs.Itiscomplexandexpensive,butverypowerful.Therearemanyalternativeswithscaleddownfeaturesandprices,andsomeareevenfree.Examplesofconsumer‐levelproductsincludeAdobePhotoshopElements($70.00viaUCSDBookstore),GooglePicassa(free).Therearealsoagrowingnumberofonlineeditors.CNET.comrecentlyreviewed15popularproducts(http://cnet.com).

Whatisthebestwaytomanagedigitalimagecollections?Manyoftheconsumerlevelphoto‐editingprogramsalsoprovidetoolsforbrowsing,sorting,andapplyingkeywordsanddescriptions.InadditiontoPhotoshopElementsandPicassacitedabove,thereisiPhoto(Mac),WindowsLivePhotoGallery(Win),CorelMediaOnePlus(Win),Shoebox(Mac),andmanymore.


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Digitalimageeditingissometimesreferredtoas“post‐processing”orworkinginthe“digitaldarkroom”.Togetthebestresults,mostexpertsdescribeaspecific“workflow”oralogicalorderofsteps.ThedirectionsthatfollowassumeyouareworkingwithAdobePhotoshop,howeversimilarprocessesmaybeaccomplishedwithotherimageeditingprograms.

I.BASICIMAGEEDITINGPROCESS(makingglobalchangestotheimage):

1. Open:FromtheFilepulldownmenu:chooseOpenandselectthephototobeedited.

2. Createacopyforediting:FromtheFilepulldownmenu:chooseSaveAs.

Thedialogbox(left)willappear.a. IntheFileName(Mac:SaveAs)field(redarrow):

changetheimagenametoindicatethatthisistheeditedversion.Forexample,append“copy,”“_ed”or“_edit”totheendoftheoriginalfilename.

b. FromtheFormatpulldownmenu(bluearrow):selectPhotoshop.

c. SelectyourdestinationfolderandclickSave.

3. Rotate:Ifyourphotoishorizontalwhenitshouldbevertical?Orverticalinsteadofhorizontal?Orupsidedown?Hereiswhattodo:a. FromtheImagepulldownmenu:click+holdonRotate

Canvas(redarrow);asubmenuwillappear(bluearrow).

b. Selectappropriateaction:900CW,900CCW,or1800.c. Savethesechanges.

4. Adjustbrightnessandcontrast:Thetechniqueslistedbelowstartwiththesimplestandmovetothemorecomplex.Trythemintheorderinwhichtheyarelisted–onlymovingtothenextIFyouarenotsatisfiedwiththeresults.

ThesetechniquesarefoundintheImagepulldownmenuunderAdjustments(redarrow).Alladjustmentscoveredherearefoundintheupperportionofthesubmenu(withinbluebox).a. AutoLevels:theeasiestoptionthatsometimesworks

fine.Iftheresultisnotsatisfactory,selectUndo(Editmenu)orclickonthepreviousstepintheHistoryPalette,andmoveontothenextoption.

b. AutoContrast:Itworksontheoverallbrightnessandcontrast,butdoesnotalterthecolorsinthephoto.Again,UndoorusetheHistoryPaletteandmoveontothenextoptionifyoustillarenotsatisfied.


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c. Levels:ApowerfultoolalsofoundintheImagemenuunderAdjustments.TheLevelshistogramdisplaysthenumberofpixels(ontheyaxis)vs.thecolorofthepixels(onthexaxis)fromblack(0)towhite(255).

Mostphotoslookbestwhenthefullcolorrangeisusedandthehistogramspansfromblack(0)towhite(255).Ifblacksandwhitesaremissing,theimagemaylookflatandwashedout.

Ontheotherhand,sometimesimagestakenonarainyorfoggydayactuallydonothavethefullyblackorwhiteregionsofthehistogram.Soalwaysconsideryourpictureandhowyouwantittolook,whenmakingtheseadjustments.

UsingtheInputlevelsliders,youcanchangebrightness,contrast,andtonalrangebypickingwhatiscompletelyblack,completelywhite,andmiddlegray.

TherearetwowaystomodifyimageLevels:

SlidersbelowInputHistogram:• BlackPointslider(redarrow)• WhitePointslider(bluearrow)• Midtoneslider(yellowarrow)

EyeDroppers• BlackPointeyedropper(redarrow)• WhitePointeyedropper(bluearrow)• Midtoneeyedropper(yellowarrow)

♪NOTE:InLevelsandmanyoftheothertools,thereisawaytoResetyourchangesandstartoverwithoutleavingthedialogbox.

• PC:clickandholdthealtkey.• Mac:clickandholdtheoptionkey

TheCancelbuttonchangestoReset(redarrow).ClicktheResetbuttonandcontinuetoexperimentwithlevelsuntilyougetthebestpossibleeffect.


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5. AdjustColorBalance:Again,thestepslistedbelowstartwiththesimplesttechniqueandmovetothemorecomplex.Trythemintheorderinwhichtheyarelisted–onlymovingdownifyouarenotsatisfiedwiththeresults.Alltools/techniquesarefoundintheImagemenuunderAdjustments.

a. AutoColor:Thisistheveryeasiestoptionanditsometimesworksfine,especiallywhenyouhaveagoodmixofcolorsinyourphoto.Iftheresultisnotsatisfactory,selectUndo(Editmenu)orclickonthepreviousstepintheHistoryPalette,andmoveontothenextoption.

b. ColorBalancecanbeusedtomakesubtlechangesinthecolorofyourphotos.Itonlytakesasmallchangetocreatealargeeffectinyourimage.Becarefulnottooverdoandcreateunrealisticresults.

• Adjustcolorlevelsusingsliders(redbracket).

• Typically,workwithMidtonesselectedintheToneBalancebox(yellowbox).

• PreserveLuminosityshouldbechecked(bluebox)oryourpicturewillgetdarkerorlighterasyouchangecolors.

6. Crop:TheCroptool(locatedinthetoolbar,seeredarrow)allowsyoutoselectaportionofyourphotoanddeleteeverythingoutsidethearea.

a. Selecttheportionofthepictureyouwanttoretainb. Modifythearea,asneeded,byusingthehandlesonthesideoftheselection

box.

c. HitEnterandyourpictureswillbecropped.

Ifyouchangeyourmind,rememberyoucanalwaysselectUndo(Editmenu)orclickonthepreviousstepintheHistoryPalette,andmoveontothenextoption.


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7. Resize:Youmaywanttochangethesizeorresolutionofyourphotodependingontheintendeduse.

• Trytoresizeonlyonetime,asrepeatedresizingtendstoaddblurrinesstoyourpicture.

• Makeofcopyofthefull‐sized,editedimage(preferablyinPhotoshopformat)beforeyouchangeimagesize,resolution,orfiletype.Thiswillenableyoutogobackatalatertimeandmakecopiesforotherpurposes.

a. FromImagepulldownmenu,selectImageSize(redarrow).

b. TheImageSizedialogboxprovidesameanstomanipulatemultiplevariables:

PixelDimensions(redbox)andDocumentSize(greenbox)arelinked;changingoneaffectstheotherANDthefilesize(redarrow).

Resolution(bluebox)canbeindependentlychanged.Seediscussionbelowaboutwhatresolutiontoselect.

ConstrainProportions(greenarrow)shouldbecheckedtoensureheighttowidthratioaremaintained.Aninterpolationalgorithm(bluearrow)shouldbeselectedaccordingtowhetheryouareincreasingordecreasingimagesize.

• Foruseinemailortheweb:Remembersmallerfilesizesloadfasterandareeasiertosendviaemail.Twocomponentscontributetofilesize,resolution&imagesize.Oldercomputermonitorshavearesolutionof72dpiwhilenewermonitorshavearesolutionof96dpi.Ifyourimagehasahigherresolutionitwillnottranslatetoahigherviewqualityoncomputermonitors.

‐ IftheoptionResampleImageisselected(lookjustbelowthegreenarrow),theimagesizewilldecreasewhenyoureducetheResolution.

‐ ToadjusttheResolutionofyourimagewithoutaffectingtheimagesize,unchecktheResampleImageoption.

• Foruseinprinting:Youshouldusearesolutionatleastequaltothedotsperinch(DPI)ofyourprinter,butusingmoreusuallyproducesabetterresult.


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8. Sharpen:ThesharpeningprocessshouldonlybedoneAFTERallotherstepsofphotoediting.Regardlessofthemethodused,DONOTOVERSHARPEN.Itwillinducenewartifactsandshiftsintheimagecolors.Herearetwomethods,easiestfirst.

a. Sharpen:FromtheFilterspulldownmenu,selecttheSharpenmenu(redarrow)andthenselecttheSharpenfilter(greenarrow).Thisactionwillsetadefaultpercentagetoyourimage.Itisaquickfixandsometimesworks.

b. UnsharpMask:FromtheFilterspulldownmenu,selecttheSharpenmenu(redarrow)andthenselecttheUnsharpMask...(yellowarrow).Thisiseffectivelyahigh‐passfilterthatdetectsedgesandaddscontrastalongtheedges.

TherearethreesettinginUnsharpMask.Whilethereisnoclearconsensusontheorderandvalueforeachsetting,Iusetheminthefollowingorderandselecteffectsthatlookgoodonthepreviewwindowat100%.

i. Radiussetting(redarrow)establishesthesizeofthesharpeningeffectalongeachperceived“edge”.

OnegenerallystartswiththeRadiusaround1.0‐1.5pixels.

• Forphotoswithalotoffinedetail,lowertheRadiussettingto0.5‐1.0.

• Forphotoswithlessdetail,raisetheRadiusto2.0‐4.0

ii. Amountsetting(greenarrow)dictatesthestrengthofthesharpeningbydetermininghowmuchcontrastisaddedattheedges.

• WithasmallRadius,uselargerAmount.• WithalargeRadius,useasmallerAmountofsharpening.Therearenospecific

numberstorecommend.

iii. Thresholdcontrol(yellowarrow)isbasicallyanoise‐reductionsetting.IttellsPhotoshoptoignoreacertainamountofdifferencesbetweenpixelswhensharpeningbysettingtheminimumbrightnesschangethatwillbesharpened.Itenablesyoutoavoidoversharpeninglightlytexturedareas,whilestillsharpeningmorepronouncededgesandleavingmoresubtleedgesuntouched.OnceRadiusandAmountareset,decreaseThresholduntilunwantednoiseandotherartifactsappear,thenraiseitslightly.


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SaveAs:Nowisthetimetoselectafiletypeforyourpicture.Theoneyouchoosewilldependonhowyouintendtousetheimage.

Listedbelowarethemostfrequentlyusedgraphicfileformatsandtheirextensions:

a. PSD–default(“native”)fileformatforAdobePhotoshop.Sinceitpreservesalloftheeditingcapability(e.g.,layers,transparency,etc.),itisgoodpracticetokeepaPSDversionofyouroriginalfileandanotheroftheeditedforsubsequenteditsandadjustments.

b. JPG–theformatdevelopedbytheJointPhotographicExpertsGroup.Itisacross‐platformfileformat(MacandPC)primarilyusedforwebandMicrosoftPowerPointapplications.JPEGisbestforphotoswhenyouwanttokeepthefilesizesmall(withonlysomelossinquality).WheneveraJPGfileisclosed,thefileiscompressed.Therefore,youreditingshouldbedoneonthePSDfileifpossibleandthensavedasaJPG.MultiplesavesofaJPGimagedegradeimagequality.

c. TIFF–TaggedImageFileformat.Across‐platformfileformatprimarilyusedforprintingapplications.Itproduceslargefileswithnolossinquality.

SectionII:Techniquesthataddressspecificproblems/needs

Correctingflawsistypicallydoneafterlevel,brightness/contrast,andcolorcorrectioniscompleted,butbeforeyoucroporsharpentheimage..

1. Dust&Scratchesfilteristheeasiest,butmostprimitivesolutionbecauseitcandegradeyourimage.Itworksbestiftheproblemarealacksalotofdetailandwhenpossibletheareawithdustorscratchesisselected.

a. TofindtheDust&Scratchesfilter:i. GototheFilterpulldownmenu(redarrow)

ii. ClickandholdontheNoisecategory(yellowarrow)iii. SelectDust&Scratchesfromthesubmenu.

b. Dust&Scratchesdialogbox:

i. SetThresholdtozero(redarrow)ii. DragtheRadiusslider(greenarrow)untilthedustor

scratchesgoesaway.


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2. CloneStamptoolcanbeusedtoremoveeverythingfromsmalldustmarkstolargeunwantedobjectsfromyourphoto.Itisaretouchingtoolthatletsyoucopy(sampleorclone)pixelsfromoneareaandthenpastethemontoanotherarea.Forexample,toremoveadustspotintheskyofyourpicture,youwouldsamplethepixelsinanadjacentclearpartofthesky,andthenusethosepixelstocoverthedustspot.

a. SelecttheCloneStampToolfromthetoolbox(bluearrow).BesureyouhaveselectedCloneStampandnotPatternStamp.

b. Yourbrushsizeandshapedepends(inpart)onthesizeoftheflawyouaretryingtocorrect.Tochooseabrush:

• ClickthetinyarrowtotherightofthebrushiconontheCloneStampOptionsBar(attopofthescreen,belowtheMenuBar)Orright‐clickonthephototobringupthebrushsettingsdropdownmenu.

• Masterdiametersetting(redarrow)o Tocorrectminorproblems,useabrush

diameterthatisslightlylargerthantheflawyouwanttocorrect.

o Toremovelargeunwantedobjects,useasmallbrush(5‐10pixels)andsamplefrommanysourcestoblendthepatch.

• Hardnesssetting(greenarrow)o Tomakeprecisesamplesofyoursource

pixels,itisbettertouseaveryhardbrush(~100%).

♪NOTE: Onceyouhaveabrushselected,youcaneasilyrefineitsdiameterwhilethebrushsitsovertheareayouwishtopaint.Theleftbracket[makesthebrushsmaller,whiletherightbracket]‐‐makesthebrushbigger.Thisshortcutworkswithanytoolthathasabrush.

c. Thecloningprocess:• Movethecursorovertheareaofthepicturetobecloned(the“sample”).

• DepresstheAlt(Mac:Option)key.Thecursorwillchangetoatarget.Nowclickthemousetomarkfromwherethepixelswillbesampled.

• Moveyourbrushovertheareayouwanttorepair.Clickandpaintoverthearea.Noticethatthepointfromwhichyousampled(markedbyacrosshair)moveswithyourbrushasyoupaint.

• Repeatthelasttwostepsasneeded.


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♪NOTE: Zoom(magnify)theareaofinteresttomoreeasilyworkwiththeCloneStampandothertools.Tomagnifyanimageyouhaveseveraloptions:

1. Usethezoomsliderinthenavigatorpalette.

2. Typingalargernumberinthe%magnificationboxofthenavigatorpaletteorthestatusbar.

3. Selectthemagnifyingglassfromthetoolbar.Thenclickontheimage.A+signwillappearinsidethemagnifyingglass.Eachtimeyouclickthetoolontheimage,themagnificationwillincrease.

4. UsetheshortcutCtrl+plussign(PC)orCmd+plussign(Mac).Eachtimeyouusetheshortcut,themagnificationwillincrease.

♪NOTE: Todemagnifyanimageyouhaveseveraloptions:

‐ Usethezoomsliderinthenavigatorpalette.

‐ Typeasmallernumberinany%magnificationbox.

‐ Holddownthealtkeywhileusingthemagnifyingglassmakesitworkinreverseanda‐(negativesign)showsupinsidetheglass.Eachtimeyouclickthetoolontheimage,themagnificationwilldecrease.

‐ UsetheshortcutCtrl+minussign(PC)orCmd+minussign(Mac).Eachtimeyouusetheshortcut,themagnificationwilldecrease.

3. TheHealingBrushtoolworksalotliketheCloneStamptool.Butinsteadofcoveringtheimperfectionswithacopyofsampledpixels,theHealingBrushblendsthesampledpixelsintotheimperfectionssuchasscratches,blemishes,etc.

a. ClickontheHealingBrushiconinthetoolboxandselecttheHealingBrush

b. Checkthesettingsintheoptionbar,includingbrushdiameterandblendingmode.Sourceshouldbe“sampledfromtheimage”

c. Alt‐click(Mac:Option‐click)neartheimperfectiontodefinethestartingpointofthesample.

d. Paintovertheimperfection.Ifalignedisselected,theHealingBrushtoolwillrememberthestartingpointbetweenmouseclicks.

4. TheSpotHealingBrushtoolisgreatifyouonlyneedtofixsmallimperfections(likeaspotordustmarkinthesky.Thistooldoesnotrequireasourcetobespecified.Insteaditautomaticallysamplestheadjacentpixelsanddabsawaytheproblem.


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5. TheRedEyetoolisfoundinthesametoolbarboxastheHealingBrush.Selectthetoolandclickoneacheye.Itdoesnotalwayswork,butitistheeasiestoptiontotry.

6. TheBurnorDodgetoolcanbeusedtochangetheexposureofaspecificallydefinedarea.Thenamesofthesetoolscomefrompre‐digitaldarkroomtechniqueswherelightcouldbeblockedout(dodged)fromapartoftheimagetolightenorlightcouldbeconcentratedtodarken(burn)anarea.a. Dodge(yellowarrow)lightenspixels

Burn(greenpixels)darkenspixels.

b. BeginwiththetoolsettoMidtones.Pickawide,soft‐edgedbrush.UsealowExposuresetting(10‐15%),sincelowerthesetting,thelessdrastictheeffect.

c. Thesetoolsworkbestongrayscaleimages.Withcolorimages,usethesetoolssparinglyortheresultscanbeunnatural.

♪ NOTE: TheSpongeTool,notcoveredinthisworkshop,canbeusedtoincreaseordecreasethecolorsaturation.

PartIII.CreativeTechniqueswiththeFilterGallery

1. TheFilterGalleryisfoundintheFiltersmenu.Whenitopens,theworkareadividedinto3panels:

a. Theimageisseenontheleftside(redbox).Youcanchangethemagnificationclickingonthe‐+orbyselectinga%magnificationfromthecontrolsatthebottomleftofthepicture(redarrow).

b. Thefilterselectionisshowninthemiddlepanel(greenbox).Itisdisplayedbycategoriesthatcanbeexpandedbyclickingontherightpointingarrow.

c. Withafilterselected,usethesliderscontrols(bluebox)tochangespecificcharacteristicsoftheselectedfilter.

2. Multiplefilterscanbeappliedtothesameimage.Theyappearinalist(bluearrow)thatworksjustlikethestandardPhotoshoplayers.Itnamesthefilterselectedandhasaneyeicontoshowthatitisvisible.Youcanclickonthepageiconatthebottomofthisboxandcreateanewlayerthatcanbeusedforanotherfilter.Youcanapplyasmanyfiltersasyoulikeandchangetheorderbydraggingthelayerupanddown.

3. Ifyouknowexactlywhatfilteryouwanttoapply,youcanselectiffromthelist.TheFilterGallerywillthenopenwithyourchosenfilterselectedandapplied.