Transcription of TAGA Annual Technical Conference 2002 W Craig …
1 FujiFilm 2002 ICC color management for print productionICC color management for print productionTAGA Annual Technical Conference 2002W Craig ReviePrincipal ConsultantFuji Film Electronic Imaging LimitedICC Chair of the Graphic Arts Special Interest Group FujiFilm 2002 Tutorial outlineTutorial outline About the ICC ICC color management concepts Creating ICC profiles Using ICC profiles Defining an ICC-based workflow FujiFilm 2002 About the ICCA bout the ICC ICC History ICC Objectives ICC Membership Working groups Details from FujiFilm 2002 ICC History - some milestonesICC History - some milestones 1990 PostScript Level 2 released by Adobe 1993 FOGRA Conference - Intercolor consortium formed 1994 Apple s ColorSync format adopted 1994 Version 2 ICC profile format defined 1995 Windows 95 with ICM 1999 PDF has support for ICCB ased colorspaces 2000 Photoshop 6 released 2001 Version 4 ICC profile format defined 2002 PDF/X-1a (and possibly PDF/X-3)
2 Standardized FujiFilm 2002 ICC ObjectivesICC Objectives Open systems color management Portable, standard color profile format Framework independent of device capabilities Technical basis and broad membership Develop a common understanding of color Not limited to print production Basis of profile connection space is a reflection print which may limitareas of application FujiFilm 2002 ICC Membership and OrganizationICC Membership and Organization Founding members Regular members Honorary members Observers Steering committee Founding members + elected members Chair, vice chair.
3 Secretary and Technical secretary Lars Borg [Adobe], Uwe-Jens Krabbenhoeft [Heidelberg],Kip Smythe [NPES], Tony Johnson [London College of Printing] FujiFilm 2002 Working groupsWorking groups Focus on specific areas Examples: Architecture Working Group Workflow Working Group Graphic Arts Special Interest Group Email discussion groups + 4 meetings per year FujiFilm 2002 Tutorial outlineTutorial outline About the ICC ICC color management concepts Creating ICC profiles Using ICC profiles Defining an ICC-based workflow FujiFilm 2002 ICC color management conceptsICC color management concepts Basic colorimetry, CIE standard observer RGB additive and CMY(K)
4 Subtractive color models Device independent color color transforms FujiFilm 2002 How we see colorHow we see colorCIELab and CIEXYZ standards based on CIE standard observer describe colors as we see them used in both PostScript and PDFRod cellsCone cellsResponse of conecells to differentfrequencies of lightThe CIE standard observer FujiFilm 2002 color illusionsColor illusionsSubtractive colorSubtractive colorStart with white and subtractred, green and blueMany (but not all) colors can besimulated in this wayAdditive colorAdditive colorStart with black and add red, green and blue FujiFilm 2002 Each device sees color differentlyEach device sees color differentlyImageImagedisplaydisplayDigit alDigitalcameracameraScannerScannerPrint ingPrintingpresspressInk jetInk jetprinterprinterPhotographicPhotographi cprinterprinterHow can we convertcolors from one deviceto another?
5 FujiFilm 2002 Device dependent solutionDevice dependent solutionColourtransformjungleImageImaged isplaydisplayDigitalDigitalcameracameraS cannerScannerPrintingPrintingpresspressI nk jetInk jetprinterprinterPhotographicPhotographi cprinterprinterM x NM x Ntransformstransformsrequiredrequired FujiFilm 2002 Device-independent solutionDevice-independent solutionImageImagedisplaydisplayDigitalD igitalcameracameraScannerScannerPrinting PrintingpresspressInk jetInk jetprinterprinterPhotographicPhotographi cprinterprinterStandardcolourspaceColor transform fordevice to standardcolor space andfrom standard colorspace to deviceTAGTAGTAGTAGTAGTAGM + NM + Ntransformstransformsrequiredrequired FujiFilm 2002 How ICC profiles workHow ICC profiles workBtoA tablesAtoB tablesICC ProfileInk percentage[CMYK]Standard color space[CIEXYZ or CIELab]
6 Given a colour calculate inkpercentage required to reproducethat colourCalculate colour produced bygiven ink percentages FujiFilm 2002 Basic color transform elementsBasic color transform elementsparametric curveparameters defining oneof a standard set offunctions in profilee1 e2 e3e4 e5 e6e7 e8 e9matrixmatrix coefficientsstored in profilee1 e2 e3e4 e5 e6e7 e8 e9e10e11e12matrix with offsetmatrix coefficientsstored in profile1-D LUT count samplescurvevaluesstored inprofilemulti-dimensionalLUTvalues at each nodeof the 3- or 4-D tablestored in profile FujiFilm 2002 Putting the elements togetherPutting the elements togetherCMYK 1-D tablesLab 1-D tables4-D LUTAToB tag from printer profileCMYKLabe1 e2 e3e4 e5 e6e7 e8 e9matrixparametric curvesRGBtags from monitor profileCMYK 1-D tablesLab 1-D tables3-D LUTBToA tag from version 4 printer profilee1 e2 e3e4 e5 e6e7 e8 e9e10e11e12'M' 1-D tablesMatrix with offsetLabCMYK FujiFilm 2002 Example ICC ProfileExample ICC ProfileA2B0A2B1A2B2A2B3B2A0B2a1B2A2B2A3 HeaderPublicPrivateICC Profile FujiFilm 2002 ICC color management concepts (2)ICC color management concepts (2)
7 Rendering Intent Profile connection space (PCS) color management Module (CMM) FujiFilm 2002 color gamut comparisonColor gamut comparisonSolid shape indicatesgamut of print processWire frame indicatesgamut of monitorWhen printing colorsviewed on screen somekind of trade-off must bemade to determine howwe should map onecolor gamut to the other FujiFilm 2002 Gamut mapping depends on page elementGamut mapping depends on page elementIllustrationsTinted AreasTextPhotographsCompany logo FujiFilm 2002 ICC Rendering IntentsICC Rendering Intents Four ICC Rendering Intents define gamut mapping Absolute Colorimetric.
8 Measurement (relative to illuminant) of outputcolor should match that of input color if possible Relative Colorimetric: measurement (relative to paper) of output colorshould match that of input Perceptual: color images should be transformed to produce desiredappearance on the output Saturation: color transforms should maintain saturation in colors wherepossible FujiFilm 2002 Perceptual IntentPerceptual IntentColor images should be transformed to producedesired appearance on the output - but how?Inputprofile 1 OutputprofilePCSI nputprofile 1 Images and inputprofiles are createdindependently of theoutput profileWe need to agree a means todetermine 'desired appearance'with respect to the PCS?
9 FujiFilm 2002 Profile connection space definitionProfile connection space definition(Perceptual Intent)(Perceptual Intent)CIE 1931 standardcolorimetric observeradapted to viewingenvironment20% surroundAh yes, not abad looking virtual printD50, 500 lux lightsourceMedia White Point hasneutral reflectance of89% (Dmin )Media Black point hasneutral reflectance of0,30911% (Dmax ) FujiFilm 2002 Now we can use Perceptual IntentNow we can use Perceptual IntentColor images should be transformed to producedesired appearance on the outputInputprofile 1 OutputprofileInputprofile 1 PCSOn input images and/or profilescan be adjusted to achievedesired result on (virtual)reference mediumOutput profile creators can assumethat images have been adjusted toachieve desired appearance andcan perform necessary gamutmapping for printer FujiFilm 2002 Open question: How big / what shape is theOpen question: How big / what shape is thePCS PCS gamut?
10 Gamut? This is at present undefined Given the density range that has been defined givesus an idea of size ICC is studying the advantages and disadvantages ofdefining the PCS gamut more precisely Perceptual gamut mapping is vendor specific -"beauty is in the eye of the profile creator" FujiFilm 2002 color management Module (CMM) color management Module (CMM)A2B0A2B1A2B2A2B3B2A0B2a1B2A2B2A3 HeaderPublicPrivateA2B0A2B1A2B2A2B3B2A0B 2a1B2A2B2A3 HeaderPublicPrivateInputtransformOutputt ransformRendering IntentProfile fromdocumentProfile fromprinterCMM - often part of OS usuallymore than one optionCombinedtransform FujiFilm 2002 color management Module (CMM) color management Module (CMM) Applies transforms implied by profile data No formal ICC definition Why multiple CMMs?
