VisualSimulationofCRPC1~CRPC7

UnderlyingFactorsforConsistentColorAppearance(CCA)anddevelopingCCAmetric

ElenaFedorovskaya&RobertChung- RITDavidHunter&PierreUrbain- ChromaChecker.com

CRPC1 CRPC2 CRPC3 CRPC4 CRPC5 CRPC6 CRPC7

CMYKpictorialcolorimages,outputtedtoISO15339-2CRPC1~CRPC7referenceprintingconditions,areassumedtohaveconsistentcolorappearancedespitetheircolorimetricdifferencesinwhitepointandgamutvolume

• WeplantotestthisassumptionandusethevariablesunderlyingtheCRPCstodeviatefromCCA.• InthiswaywecanexperimentallyquantifytheeffectsofGrayBalance,ToneScaleandhueanglesofCMYRGBsolids onCCAandproposeametricfortheuseingraphiccommunications.

CCAvs.ColorImageMatch

ConsistentColorAppearance ColorImageMatch

Definition A measureofvisualconsistencyamongmultipleimages(1)ofthesamescenereproducedindifferentreferenceprintingconditionsor(2)ofdifferentscenesinonereferenceprintingcondition

Ameasureofvisualmatchbetweenareferenceimageandasampleimageofthesamesceneinthesameviewingconditions

Reference(s) Multiplereferenceprintingconditionswithsimilartoneandcolorcharacteristics,butdifferentcolorgamut,e.g.,CRPC1~CRPC7

Aspecifiedreferenceprintingcondition,e.g.,CRPC6

Applications Productcampaignwhereby differentprintingprocessesandsubstratesareusedforpackaging,labeling,advertising,etc.

Colorproofsusedincommercialandpublicationprinting

TheoreticalBasis• AdjacentCRPCs,intermsofpaper,solids,andgamutvolume,areunequal.

L* a* b* L* a* b* L* a* b* L* a* b* L* a* b*CRPC1 85 1 5 59 -24 -26 56 48 0 80 -2 60 37 1 4 84,280CRPC2 87 0 3 57 -28 -34 52 58 -2 82 -2 72 30 1 2 151,311∆EabCRPC2 87 0 3 57 -28 -34 52 58 -2 82 -2 72 30 1 2 151,311CRPC3 95 1 -4 60 -26 -44 56 61 -2 89 -3 76 32 1 1 165,764∆EabCRPC3 95 1 -4 60 -26 -44 56 61 -2 89 -3 76 32 1 1 165,764CRPC4 89 0 3 55 -36 -38 47 66 -3 83 -3 83 23 1 2 253,711∆EabCRPC4 89 0 3 55 -36 -38 47 66 -3 83 -3 83 23 1 2 253,711CRPC5 92 0 0 57 -37 -44 48 71 -4 87 -4 88 19 0 1 331,416∆EabCRPC5 92 0 0 57 -37 -44 48 71 -4 87 -4 88 19 0 1 331,416CRPC6 95 1 -4 56 -37 -50 48 75 -4 89 -4 93 16 0 0 389,023∆EabCRPC6 95 1 -4 56 -37 -50 48 75 -4 89 -4 93 16 0 0 389,023CRPC7 97 1 -4 54 -42 -54 47 78 -10 90 -4 103 14 0 0 525,551∆Eab

CRPC

2.0 6.7 6.8 10.0

4.2 6.4 5.2

9.2 9.1

2.0

5.1 6.1 4.0 5.4 3.2

10.7 10.6 5.0 8.1 2.2

6.5 4.2

9.3 12.7 10.3

Paper C100 M100 Y100 K100

3.0 9.2 11.0 12.2 7.3

17%

35%

GamutVolume

GamutVolumeDiff.

80%

10%

53%

31%

TheoreticalBasis• CRF(CumulativeRelativeFrequencyof∆E00) andthe95th percentile∆E00‡betweenadjacentCRPCsareunequal.

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∆E00

CRF(CRPC1-CRPC2)

(CRPC2-CRPC3)

(CRPC3-CRPC4)

(CRPC4-CRPC5)

(CRPC5-CRPC6)

(CRPC6-CRPC7)

95th percentile ∆E 00

(CRPC1-CRPC2) 7.24(CRPC2-CRPC3) 6.56(CRPC3-CRPC4) 9.86(CRPC4-CRPC5) 4.18(CRPC5-CRPC6) 3.26(CRPC6-CRPC7) 4.03

‡ CRFandthe95th percentile∆E00 areadoptedbyCGATSTR016toassesscolorimetricalcolordifferenceandprintconformance.

Method

• Chooseonereferenceprintingcondition– CRPC4• Producevariationsfromthisreferenceprintingcondition

1) gamutchangesonly,thusmaintainingCCA2) alterationsofoneorcombinationofhueanglesofsolids,grey

balance,andtonereproduction,thusviolatingCCA

Anyoftheabovedatasets,1)and2)maybealteredinitsdevicespacetoproducethesamecolorimetricdifference.

Approach:varyprintingconditionstoselectivelyaltergamut,tonereproductionandgraybalance

• Measurechangesasequalstepsusing95th percentile∆E00• (Othercolorspacescanpotentiallybeused)

• PrintimagesselectedbytheCIETC8-16ondifferentsubstratesincludingOBA• ConductpsychometrictestsaskingobserverstoidentifyimageswithCCAfrommultiplevariationsofthesamesceneanddifferentscenes• ProposeaCCAscale• PresentattheTC8-16meeting

FromFedorovskaya,Chung,Hunter,Urbain,TAGA2017

EXAMPLEOFCOLORDATASETCHANGES

AlteringTonereproductionofthereferenceCRPC4datasetwhilemaintaininggamutvolumeandgraybalanceusing95th percentile∆E00 asashiftparameter

• CRPC4vs.CRPC4(Tonereproductionaltered)• Differenttonereproduction• Samegamutvolume,95th percentile∆E00,andgraybalance

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a*/b*

%DotArea

CRPC4 CRPC4(TR)

Gamutchangewithconstanttonereproductionandgreybalance.VerificationoftheAlteredDatasettoCRPC4• CRPC4vs.CRPC4(Small)

• Differentgamutvolume• Same95th percentile∆E00,tonereproduction,andgraybalance[Darkness=100– L*]

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Definitionsusedintheexperiment

• Consistencyofcolourappearanceisdefinedasthedegreeofvisualconsistencyand/orsharedvisualappearancethatasetofimagespossessesalbeitapresenceofvisualdifferences.• Thisconsistencyvariesaccordingtoprintingconditionsandcanbeaffectedbypapersubstrates,inks,environments,printingdevicesandprintingparameters,suchas,forexample,colourbalanceandcolourgamut,amongothers.• Thisconsistencyofcolourappearanceisanattributeofanimagesetthatmakestheimagesfromthesetbelongtothesamefamilytoavaryingdegree.• Thisdefinitionisappliedtothesamesceneprintedindifferentprintingconditions,andalsotothedifferentscenesprintedinsimilarprintingconditions.Inthelattercasethesedifferentscenescaninvokeasensethattheywereallprintedaccordingtothesamespecifications,includingthedevicegamut,inks,andtheprinter.

• Observersarepresentedwithtwocontrolimages(blue),andtwoof3testimages(yellow)differinginTR,GBorNone,ofthesamescene.• Observersareaskedtoselectatestimagethatappearstoyieldmorecolorconsistencyinthetriplet.• Therearethreepairsperscene.• Eightscenesaretested.

Test_2

Control_1(small)

Control_2(Large)

Test_1

ExampleexperimentalproceduretotestCCAforasinglescene

ExampleofexperimentalproceduretotestCCAofmultiplescenes• Observersarepresentedwithsevencontrolimages(blue)ofdifferentscenes.• Observersareaskedtoselectoneofthethreetestimages(yellow)thatappearstoyieldmorecolorconsistency.• Eightscenesaretested.• 12Observersparticipatedinbothexperiments

Scene_3(CRPC4)

Scene_1(CRPC4)

Scene_5(CRPC4)

Scene_2(CRPC4)

Scene_6(CRPC4)

Scene_4(CRPC4) Test_1

Scene_7(CRPC4)

Test_2 Test_3

Roman16_02_midtoneGRAYBALANCE TONEREPRODUCTION CRPC4

GRAYBALANCE 29 34TONEREPRODUCTION 7 33CRPC4 2 3

Exampleofdataanalysis.PairedComparisonoftestimagesforthesamescene.• Foreveryscene,pairedcomparisondatawerecollectedasa3x3matrixacrossparticipants.Eachlocationisthenumberoftimestheimageinthejth columnwaschosenovertheimageintheith row.• Forexample,theCRPC4imageischosenovertheGB-alteredimage34timeswheretheGB-alteredimageischosenonlytwiceovertheCRPC4image.

ColorConsistencyvsDevice-based95th percentile∆E00

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GB

CRPC40

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Devic

e-based9

5thpercentile∆

E 00

ColorConsistency(pairedcomparisonexperiment)

ColorConsistencyvsDevice-based95thpercentile∆E00

R2=0.99

Studymilestones

• CharacterizeprintingconditionsvariationsanddevelopICCprofiles–September– October2017• Produceexperimentalimagesets- November2017• Runpilotexperiments- December2017• Finalizetestingmethodologyandconductmainexperiment- January- February2018• Analyzeexperimentaldata– February- March2018• Presentresults- March-April2018• Submitpaper– April-May2018