PPI vs. DPI: what's the difference? - 99Designs

PPI, or pixels per inch, refers both to the fixed number of pixels that a screen can display and the density of pixels within a digital image. Pixel count on ... Logos,websites&more… Logos,websites,bookcovers&more… Getadesign PPIandDPIaretwoimportanttermsthatanyonewhoworkswithimagesshouldknow.Bothdefinetheresolution,orclarity,ofanimagebuteachreferstoseparatemedia—thatis,digitalversusprint. PPIandDPIareoftenusedinterchangeablywhentheyshouldn’tbe.Understandinghowtheyaredifferentandhowtoapplyeachinyourprojectswillempoweryoutoproduceaqualityprint,tooptimizedigitalimagesforwebandultimatelytosaveyourselfvaluabletime.Withthatsaid,let’sdeconstructwhatthesetermsmeanandgetintothedifferencesbetweenPPIandDPI. WhatisthedifferencebetweenPPIandDPI? — PPIdescribestheresolutioninpixelsofadigitalimagewhereasDPIdescribestheamountofinkdotsonaprintedimage. ThoughPPIlargelyreferstoscreendisplay,italsoaffectstheprintsizeofyourdesignandthusthequalityoftheoutput.DPI,ontheotherhand,hasnothingtodowithanythingdigitalandprimarilyconcernsprint. PPIresolution — WhatPPImeans PPI,orpixelsperinch,refersbothtothefixednumberofpixelsthatascreencandisplayandthedensityofpixelswithinadigitalimage.Pixelcountontheotherhandreferstothenumberofpixelsacrossthelengthandwidthofadigitalimage—thatis,theimagedimensionsinpixels.Pixels,or“pictureelements”,arethesmallestbuildingblocksofadigitalimage.Zoomintoanyimageonyourandyouwillseeitbreakupintocoloredsquares—thesearepixels. EachpixelismadeupofRGBsubpixelsPixelcountdescribeanimage’sdimensionsbasedonthenumberofpixelsPPI,orpixeldensity,describestheamountofdetailinanimagebasedontheconcentrationofpixels Withinpixelsaresub-pixels,red,greenandbluelightelementsthatthehumaneyecannotseebecauseadditivecolorprocessingblendsthemintoasinglehuewhichappearsonthepixellevel.ThisiswhyPPIutilizestheRGB(red,greenandblue)colormodel,alsoknownastheadditivecolormodel.Thisdoesnotexistinprint—onlyintheelectronicdisplayofimages,liketelevisionscreens,computermonitorsanddigitalphotography. WhendoyouusePPI? UsePPIwheneveryouareworkingwithdigitalimages.PPIismostusefulinpreparingfilesforprinting(thoughDPIwillbeusedbythephysicalprinter—seemoreintheDPIsectionbelow).AnimagewithahigherPPItendstobehigherqualitybecauseithasagreaterpixeldensity,butexportingat300PPIisgenerallyconsideredindustrystandardquality. AlowerPPIresolutionresultsinlessdetailandapixelatedimage AhigherPPIresolutionresultsinmoredetailandasharperimage BecauseincreasingthePPIincreasesthesizeofyourfile,youwillwanttouseahighPPIonlywhennecessary.Forexample,whenprintinginvolvesmanyfinedetailsonaglossysurface,it’sbesttoconsiderusingahigherresolution.Printinganimageoncanvasdoesnotrequireashigharesolutionbecausedetailsgetlostinthetextureofthematerial.PPIdoesnotreallymatterfordistributiononthewebbecausethepixeldensityofyourmonitorisfixed.A72PPIimageanda3,000PPIimagewillappearthesameonyourscreen.Itisthepixeldimensions(theamountofpixelsfromlefttoright,toptobottom)thatwilldeterminethesizeanddetailofyourimage. HowtosetuporchangePPIresolution TheNewDocumentwindowinPhotoshophasyousetyourPixelsPerInchresolutioninthebeginning Rasterprograms(softwarethatworkwithpixel-basedmedia)likePhotoshophaveyousetupthePPIresolutionrightatthebeginningwhenyoucreateadocument.YouwillfindResolutionlistedwithotherparametersintheNewDocumentwindow. Ifyouneedtoincreasetheresolutiononanimagethathasalreadybeencreated,youcanresampleit.Resamplingistheprocessofchangingtheamountofpixelsinanimage,inwhichthesoftwarewillcreateordeletepixelstopreserveimagequality. InPhotoshop,youcandothisbynavigatingtoImage>ImageSize.IntheImageSizewindow,youwillhaveoptionsforchangingthewidth,heightandPPIresolutionofyourimage.Selectthe“Resample”checkboxandsetitto“PreserveDetails”tochoosehowPhotoshopfillsinthenewpixels. TheImageSizewindowgivesyouoptionsforadjustingyourresolutioninPhotoshop YoucandecreasetheresolutionifyousetthePPItoalowervalue.Asthepixelcountdecreases,theimagesizeanddimensionsdecreaseaswell.YouincreasetheresolutionwhenyousetPPItoahighervalue.Thisallowstheimagetobeprintedatalargerprintsize. Thatsaid,itisbesttoavoidchangingthePPIonanexistingimagewheneverpossible.TheresamplingprocessrequiresPhotoshoptogeneratenewpixelsfromscratch.WhilePhotoshopisabletoreadthesurroundingpixelsandmakeasomewhataccurateguessastowhatcoloreachnewpixelshouldbe,computersarenotoriouslybadat“seeing”imagesthewayhumanscan.Thus,computergeneratedpixelscancreateunintentionalresultsonyourimage. DPIprinting — WhatDPImeans DPI,ordotsperinch,referstotheresolutionvalueofaphysicalprinter.Printersreproduceanimagebyspittingouttinydots,andthenumberofdotsperinchaffectstheamountofdetailandoverallqualityoftheprint. PrinterdotsmixCMYKinksDPIdescribestheamountofdetailinanimagebasedontheconcentrationofprinterdots DPIusestheCMYK(cyan,magenta,yellowandkey/black)colormodeltocontroltheamountofred,green,andbluelightthatisreflectedfromwhitepaper.Thisisalsoknownasthesubtractivecolormodel.Dotsofeachcolorareprintedinpatterns,enablingthehumaneyetoperceiveaspecificcolormadefromthiscombination.DPIisameasurementofthisdensity.Thesedotsareafixedsizeandresolutionisonlyaffectedbyhowmanydotsappearperinch. WhendoyouuseDPI? Whenyourdesignisgoingtobephysicallyprinted,theprinterwilluseDPI.EachmodelandstyleofprinterproducesitsownuniqueDPIbasedonitssettings.Inkjetprintersproducearesolutionaround300to720DPI,whilelaserprintersproduceimagesanywherefrom600to2,400DPI. HigherDPIcanmeanhigherresolution,butdotsizesvarybyprinter Thereisnostandarddotsizeorshape,sohigherDPIdoesnotalwaysequatetoahigherqualityprint.Onemanufacturer’sdotsmightlookasgoodat1200DPIasanothermanufacturer’sdotsdoat700DPI.Booksandmagazinesoftenuse150DPIforphotographicreproduction,andnewspapersoftenuse85DPI.AsktheprintshoporconsulttheprinterspecificationstofindtheappropriateDPIforyourproject. Imageresolutionmatters — KnowinghowtousePPIwillempoweryoutoproducehighqualityimageseverytime.AndknowinghowtonavigateDPIwillhelpyoutoeffectivelycommunicatewithprintingmachinesandprofessionalsintheprintingindustry.Unlessyouareaprinter,yourmainfocuswillbeonPPI.Butitisimportanttounderstandtheprocessofphysicalprintingifyourworkrequiresitonaregularbasis. Intheend,eventhebestdesigncanberuinedbyapoorimageresolution.That’swhyifyouwantcrystalclearqualityinyourdesigns,makesureyou’reworkingwithaprofessionaldesigner. Checkoutthisarticleongraphicdesignbasicsformoredesignknowledge. Wantpictureperfectresolutioninyourdesignprojects? Findadesignertoday! Browsedesigners ThisarticlewasoriginallywrittenbyAlexBingmanandpublishedin2013.Ithasbeenupdatedwithnewexamplesandinformation. You'rein! Youprovedusrightagain.Ournewsletterisonlyforthecoolestkids.Andyou’reoneof‘em.Getreadyforamazingstuffinyourinbox. Wantdesigntips&businesstrends(andtheoccasionalpromotion)inyourinbox? Subscriberstoournewsletterhavebeenscientificallyproventobesmarter,betterlookingandatleast50%moreawesomethanaverage. Zionks!Lookslikesomethingwentwrong. I'mafreelancedesigner Ournewsletterisforeveryonewholovesdesign!Letusknowifyou'reafreelancedesigner(ornot)sowecansharethemostrelevantcontentforyou. Signmeup! Bycompletingthisform,youagreetoourTermsofServiceandPrivacyPolicy. ThissiteisprotectedbyreCAPTCHAandtheGooglePrivacyPolicyandGoogleTermsofServiceapply. 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