2023学年完整公开课版LipMakeupProducts

LIPMAKEUPPRODUCTSTheTypes,Function,Formulation,QualityIssuesandEvaluationforLipstickHunanChemicalVocationalTechnologyCollegeHongguangLiaoOct.08,

2018AnalysisoftheTeachingMaterialTextbook:

“INTRODUCTIONTOCOSMETICFORMULATIONANDTECHNOLOGY”,

FirstEdition©2015JohnWiley&Sons,Inc.Published2015

Textbookcontents:Chapter4,Section1Authors:GabriellaBaki1andKennethS.Alexander11TheUniversityofToledo,CollegeofPharmacyandPharmaceuticalSciences2CONTENTSINTRODUCTIONOFCOLORCOSMETICSLEARNINGOBJECTIVESANDKEYCONCEPTSANATOMYANDPHYSIOLOGYOFHUMANLIPSTYPESANDDEFINITIONOFLIPMAKEUPPRODUCTSHOWLIPMAKEUPPRODUCTSMAYAFFECTTHEHUMANLIP?REQUIREDQUALITIESANDCHARACTERISTICSANDCONSUMERNEEDSTYPICALINGREDIENTSOFLIPMAKEUPPRODUCTSTYPICALLIPSTICKTYPESFORMULATIONOFLIPMAKEUPPRODCTSTYPICALQUALITYPROBLEMSOFLIPMAKEUPPRODUCTSEVALUATIONOFLIPMAKEUPPRODUCTSPACKAGINGOFLIPMAKEUPPRODUCTS3INTRODUCTIONOFCOLORCOSMETICS4LipmakeupEyelashmakeupEyelidmakeupFacialmakeupNailCarePart

of

our

regular

culture

and

fashionSelf-improvementSelf-adornmentGrooming

Sense

of

well-beingGeneral

attention

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attractionINTRODUCTIONOFCOLORCOSMETICS5HistoryofusingcolorcosmeticsTheearliestevidenceofculturalrelicslipstickinChineseisPaleolithicHongShangoddess.TheearliestforeignrecognizedfirstlipstickwasborninancientEgypt.ResistedbysomecultureinEuropeintheearlyages.Roseagaininallclasseswiththedevelopmentofcinema,photographyandtelevision.Today,itisamultibillion-dollarbusinessworldwild.INTRODUCTIONOFCOLORCOSMETICS6The

purposes

of

colorcosmetics

applicationIntheearlyages,forbeautification,maintenanceofayoungappearance,protectionofthebodyfromtheenvironment,preparationforreligiousrituals,andevenmedicaltreatment.Latestdevelopments,resistabrasiveremoval(i.e.,transfer-resistantproducts),long-lastingproductsandmultifunctionalproducts.LEARNINGOBJECTIVESANDKEYCONCEPTS7LearningobjectivesDefine:Vermilionzone;Lipbalm,Lipgloss,Lipliner,Lipplumpinglipstick,Lipstick;Mold,Molding,Flaming,Extrusion;Aeration,Bleeding,Cracking,Cratering,Deformation,Laddering,Sweating,Seams,Streaking;Rigidity,Breakstrength.Describehumanlipsforanatomicalregions,causeswiththedryness,changesduringaging.Differentiatebetweenlipstick,lipgloss,liplinerandlipbalm.LEARNINGOBJECTIVESANDKEYCONCEPTS8LearningobjectivesListvariousrequiredqualitiesandcharacteristicsforcosmeticandtechnical,whichanideallipmakeupproductshouldpossess.Describethemothedofmoldingusedtopreparelipsticksandnameitsfourbasicsteps.Explainwhypre-millingofpigmentsisimportantbeforemixingthemintothelipstickbase.Listthetypicalingredienttypesoflipmakeupproducts,andprovidesomeexampleforeachtype.LEARNINGOBJECTIVESANDKEYCONCEPTS9LearningobjectivesListthetypicalqualityissuesfortheformulationoflipmakeupproductsandexplainwhytheymayoccur.Brieflydiscussthepotentialsafetyissuesregardingleadcontaminationoflipsticks.Listtypicalcontainersavailableforlipmakeupproducts.Listthetypicalqualityorefficacyparametersthataretestedforlipmakeupproductsandbrieflydescribetheirmethodofevaluation.LEARNINGOBJECTIVESANDKEYCONCEPTS10KeyconceptsHumanlipshaveacomplexanatomyconsistingofmucosaandskin.Themostfrequentlyappliedtechniquetoproducelipsticksandlipbalmsistheprocessknownasmolding.Theusualstepsofthistechniqueinclude(i)pigmentpremilling,(ii)meltingandmixing,(iii)moldingandpackaging,and(iv)flaming.Additionaltechniquesincludemoldingwithoutflaming,simplemixingwithoutheating,aswellasextrusion.Thetypicalquality-relatedissuesoflipcareproductsincludeaeration,laddering,chipping,deformation,cratering,streaking,sweating,mushyfailure,seams,bleeding,andpoorpay-off.LEARNINGOBJECTIVESANDKEYCONCEPTS11KeyconceptsParameterscommonlytestedtoevaluatethequalityoflipcareproductsincludebreakstrength,hardness,meltingpoint,softeningpoint,colormatching,colorbrightnessandstreakiness,pay-offandglide,rigidity,viscosity,andpH.Themostfrequentlytestedefficacyparameteristhemoisturizingeffectoflipbalms.Themainingredientthatcausedsafetyconcernsregardinglipsticksislead.ANATOMYANDPHYSIOLOGYOFHUMANLIPS12StructureofthehumanlipANATOMYANDPHYSIOLOGYOFHUMANLIPS13BasichistologicalcharacteristicsofthehumanlipTheproductionofnaturalemollientsisverylowinthelipContainlesswaterandlosewaterfasterEasilydriedandchappedVeryrapidcellturnoverVerysensitivewithalotofsensoryreceptorsLackofkeratinizedcellsandmelaninBecomeflat,thinandlessshapelyandsensitiveovertimeFinelinesanddeeperwrinklesleadtobleedingTYPESANDDEFINITIONOFLIPMAKEUPPRODUCTS14LipsticksLipglossesLiplinersLipbalmsEnhancetheappearanceofthelipsbyimpartingcolorandgloss.ConsistofBase:

waxes,butters,fats,oilsandhydrocarbons,PigmentsforthecolorFlavorsandfragrancesSpecificingredientsforultraviolet(UV)protectionandaplumpingeffect.TYPESANDDEFINITIONOFLIPMAKEUPPRODUCTS15LipsticksTYPESANDDEFINITIONOFLIPMAKEUPPRODUCTS16LipglossesGivethelipsaglossylusterand,sometimes,subtlecolor.Usually,alowerviscosityandmoretransparentthantraditionallipsticks.ConsistofahigherratioofoilsandlowerratioofwaxesApplysmoothly,haveagreatershine,butdonotwearaslongasalipstickdoes.Canbeclearortranslucentorexhibitvariousshadesofopacitywithvariousfinishes,suchasmetallic,glittered,glassyandfrosted.TYPESANDDEFINITIONOFLIPMAKEUPPRODUCTS17LiplinersRedefinetheoutlineofthelips.Consistofblendsofwaxes,butters,fats,andoils,similartolipsticks;Thefinishedformulationisharderandthelevelofpigmentsisslightlylower.Liplinersaremostoftenslimpencils,orfluidsencasedinspecial“pens”,attachedafinebrushtodispensetheproducts.TYPESANDDEFINITIONOFLIPMAKEUPPRODUCTS18LipbalmsAlsocalledlipprotectants,areconsideredOTCdrug–cosmeticproductsintheUS.Temporarilypreventdrynessofthelipsandhelprelievechapping.Madeofwaxes,oils,fats,butters,hydrocarbons,additionalingredients(preventlipschappinganddrying).Usuallynotoronlyslightlycolored.TYPESANDDEFINITIONOFLIPMAKEUPPRODUCTS19FYI:Todaymanylipmakeupproductsaremultifunctional.E.g.:IncreasingtheattractivenessorprovidingprotectionagainstdrynessProtectiveeffectagainstsunlight(bycontainingasunscreen(UVfilter))HOWLIPMAKEUPPRODUCTSMAYAFFECTTHEHUMANLIP?20Lipmakeupproductsareprimarilyusedduetotheircoloring.Long-wearinglipstickstendtodrythelipsbecauseofcontainingsilicones.Lipplumpinglipstickscontainingmentholandcamphormayalsocausedryness.Drynesscanbepreventedand/ortreatedwiththeuseoflipbalmswithmoisturizingingredients.Lipcanceroccursinmenmorefrequentlythaninwomen,mayattributetothewidespreaduseoflipsticksandlipbalmswithUVfiltersbywomen.Lipbalmscontainingsunscreensmayalsobeusedtopreventthereoccurrenceofherpessimplex,sincethevirusisphotoreactivated.REQUIREDQUALITIESANDCHARACTERISTICSANDCONSUMERNEEDS21Fromaconsumerperspective,aqualitylipcosmeticproductshouldpossessthefollowingcharacteristics:AttractiveshadesHomogeneouscolorwhenappliedGoodcoverageLong-lastingeffectPleasanttasteandsmellEasytoapplyUVprotection(commonrequirement)NostainingorbleedingintothefinelinessurroundingthelipsLipglosses:provideawetandshinylookLipliners:havehighpigmentcontenttoaccentthelinesofthelips,firmenoughnottorunintothelinesaroundthelipsLipbalms:moisturizethelipsandpreventchapping.REQUIREDQUALITIESANDCHARACTERISTICSANDCONSUMERNEEDS22Thetechnicalqualitiesoflipmakeupproductscanbesummarizedasfollows:Long-termstabilityDermatologicalsafetyCreamyglidingwithoutagreasysensationFirmadherencetolipswithoutbeingbrittleandtackyHighretentionofcolorintensitywithoutanychangeinshadeAppropriaterigidityandhardnessResistancetotemperaturefrom4–40℃withouthardeningorrunning.TYPICALINGREDIENTSOFLIPMAKEUPPRODUCTS23WaxesFunctionasstructuringagents,providingrigidityandsolidity;stabilizingthesticksandallowingthemtobemoldedintoshape.Optimalcosmeticperformancebycombiningwaxeswithdifferentproperties,suchashighshine,flexibility,andbrittleness.Themeltingpointsofwaxesvarywidelydependingontheiruniquecompositionandchainlengths.Usuallymixedwithoilstoachievethedesiredsoftness.Examples:beeswax,candelillawax,carnaubawax,paraffinwax,ozokeritewax,microcrystallinewax,polyethylene,andlanolinalcohol.TYPICALINGREDIENTSOFLIPMAKEUPPRODUCTS24Oils,fats,andbuttersProvideaslipperyandsofttexturetotheformulations.Alsohaveamoisturizingeffectandactasemollients.Oilsarealsousedtodispersepigmentsandpearls.Ahighconcentration(typicallyabove50%)mayresultinagreasyandstickyfeeling.Buttersandfattyacidesterscanimprovetheadhesivenesstothelips.Lowmolecularweightsiliconesmayalsobeused,canprovideexcellentcarrierpropertiesfortransfer-resistantlipstickswiththevolatile.Examples:plantoils(castoroil,grape-seedoil,almondoil,meadowfoamoil,oliveoil,coconutoil,palmoil,triglyceride);butters(avocadobutter,sheabutter,cocoabutter);fattyacidesters(isopropylmyristate,isopropylpalmitate,isostearylisostearate,butylstearate);hydrocarbons(polyisobutene,mineraloil,petrolatum,isododecane,isoeicosane);silicones(dimethicone,cyclomethicone).TYPICALINGREDIENTSOFLIPMAKEUPPRODUCTS25ColoradditivesThemostimportantcomponentsandstrictlycontrolledbytheauthority.Typicallytypesofcoloradditives:organiccolors,inorganicpigments,lakes,andspecificortheso-calledeffectpigments.Effectpigmentsmayincludeparticles,providingpearlescenteffect,sparkle,luster,glitter,matte,metallic,andothertypesofeffects.Effectpigments:Smallerparticles(intherangeof20μm),silkyandsatineffectsandopacifythemass;Larger-sizedparticles(intherangeof120μm),highlustereffects,sparkling,orglittering,combinedwithhighbrillianceandtransparency.TYPICALINGREDIENTSOFLIPMAKEUPPRODUCTS26ColoradditivesSpecialpigmentsusuallydonotaddtoomuchcolortoformulations;therefore,theyareusuallycombinedwithregularcoloradditives.However,inlow-colorproducts,suchaslipglossesorlipbalms,theycanbeusedalone.Examples:

Inorganicpigments:Ironoxides(red,yellow,brown,andblack),titaniumdioxide,andzincoxide;Organiccolors:reds(suchasRed6,7,and21),yellows(suchasYellow6),oranges(suchasOrange5inaconcentration≤5%),andlakessuchasRed7LakeandYellow5Lake.Effectpigments:micascoatedwithironoxidesandtitaniumdioxide(whichcanprovideasparklyorglitteryeffect,asoftluster,orapearlescenteffectdependingonthecoating),andbismuthoxychloride(whichprovidesapearlescenteffect).TYPICALINGREDIENTSOFLIPMAKEUPPRODUCTS27ColoradditivesAlthoughpigmentsarenotsolubleinthemediumtowhichtheyareadded,e.g.,alipstickbasemadeofwaxesandoils,theystillcanbedispersedintheseliquidsorvehicles.Adispersionisamixtureofasubstance(e.g.,aredpigment)separatedfromanothersubstance(e.g.,lipstickbase).Theyareseparatedbecausetheydonotdissolveineachother.Tous,amelted,coloredlipstickmixmayseemasacontinuoussolution;however,underthemicroscope,youwouldseetwophasesdispersedineachother.Itmeansthatdispersionshavecomponentsthatarenotsolubleineachotherbutstillformastableandhomogenousmixture.TYPICALINGREDIENTSOFLIPMAKEUPPRODUCTS28AntioxidantsPreventrancidityandtheoxidationofsensitiveingredients.Examples:vitaminE,butylatedhydroxyanisole(BHA),butylatedhydroxytoluene(BHT).Provideprotectionagainstmicrobiologicalcontamination.Examples:parabensandphenoxyethanol.PreservativesMaskfattyorwaxodor.Shouldbeneitherirritantnortoxicbyingestion,agreeabletaste,andstableduringtheformulation.FragrancesTYPICALINGREDIENTSOFLIPMAKEUPPRODUCTS29Flavoringagentsprovideapleasanttaste.Anyauthority-approvedfoodflavoringagentcanbeusedforflavoring.Tastecanalsobeadjustedbyusingsweeteners,suchassodiumsaccharin.Lipplumpinglipstickscontainingcinnamonormentholarealsopopulartoday.Improvethetexture,application,andstabilityofproducts.Examples:talc,silica,mica,titaniumdioxide,andbismuthoxychloride.TexturizingingredientsTYPICALINGREDIENTSOFLIPMAKEUPPRODUCTS30FixativesMainlyusedinlong-lastingformulas,preventcolorsfrombleedingonthelips;theyhelpsealthelipsticksonthelips.Primarily,siliconeresinsareusedasfixativesinlipsticks.Examples:lipprotectantingredientsandUVfilters.ActiveingredientsTYPICALLIPSTICKTYPES31MattelipsticksRichinpigmentsandwaxesbutlighterinemollients.Sincetheycontainlessoil,theydeflectlightandarelessshiny.Mattescanoftenbelongerwearingthanshiniertypesoflipstick.GlossyorglazelipsticksHeavyinoilandoftencontainflavorsandscentsaswell.Theyusuallyaddshineandvolumetothelips.Generally,glossylipstickscomeinlightershades.Thecoveragetheyprovidelastslongerthanthatoflipforglosses,however,notaslongasthatofwithcrèmelipsticks.Theirmaindisadvantageisthattheywearoffquickly.TYPICALLIPSTICKTYPES32CrèmelipsticksAswellassatinandsheerlipsticks,usuallyfallbetweenmattesandglosses.Theycontainahighconcentrationofemollients,createashiny,glossyfinish.Typicallycontainpigmentswithasmallerparticlesizetoachieveasilkyeffect.Theyalsotendtowearoffquicklyand,therefore,mustbereappliedfrequently.ShimmerlipsticksAlsoknownasfrostedlipsticksContainlight-reflectingparticles,suchascoatedmicaswithalargerparticlesize,toaddlustertothecolor.Theyaremoreoftenusedforspecialoccasionsandcomeinlightercolors.TYPICALLIPSTICKTYPES33Long-wearinglipsticksUsuallytwo-partsystemsconsistingofacoloredbaseformulaandacolorlesscover.Thebasecontainspigments;therefore,itlookslikearegularlipstick.Itmayalsocontainsiliconesandhydrocarbons,whichsealinthecolor.Oncethebasedries,consumerscanapplythecolorlesscoverformulationfortheshinetokeepalipstickonalldaylong.Theformulacanbeverydrying.LipplumpinglipsticksMakelipsappearfullerbyslightlyirritatingthedelicateskinonthelipstomakethemswell.Ingredientsusedtoprovidethiseffectincludeginger,cinnamon,cayenne,camphor,andmenthol.FormulationofLipMakeupProducts34Molding:Pigmentpremilling;Meltingandmixing;Moldingandpackaging;Flaming

Astepwhereagglomeratesinthepowdercolorarebrokenupbyfinelygrindingtoprovideahomogenous,smoothandevencolortolipsticks.A“pigmentgrind”usinganoilwithatriplerollmill,beadmill,orsimilarconventionalmill,orpestleandmortarforthelaboratory-scalepreparation.Today,pre-micronizedpigments,ready-to-useliquidpigmentdispersions,andspecialeffectpigmentsdonotrequiregrinding.FormulationofLipMakeupProducts35Molding:Pigmentpremilling;Meltingandmixing;Moldingandpackaging;Flaming

Solidwaxesshouldbeheatedandmelted,makingthemcanbemixedwiththeothercomponentsandpouredintothelipstickmolds.Waxescanbeusuallymixedwiththeoilsandmeltedwiththem.Tofacilitatemixing,varioustypesofmixers/disperserscanbeused.Whenthelipstickbaseismelted,thepigmentdispersioncanbeaddedtothemeltedphaseandmixeduntilahomogeneousproductisachieved.Themixtureisslightlycooledandthenspecificpigments,preservatives,fragrances,andotheringredientscanbeaddedandmixeduntilhomogenous.Actualstepwherethemeltedlipstickmixispouredintoplasticormetalmolds.Operationpoints:Pourwhilehotorcoolslightlyandliquid(withoutsolidifying,10℃abovemeltingpoint）foruniformpigmentdisruptionandentrappedairescaping.Pourinanuninterruptedstreamavoidingtoformalayered.Pourinexcessavoidingshrinksasitcools.Placethemoldoncoolingtableuntilithardens,slicetheexcessmaterial,removedbyslightpressureandputtedintolipstickholder.Ifneeded,cutoffthetipoflipsticktoprovideeasierapplication.FormulationofLipMakeupProducts36Molding:Pigmentpremilling;Meltingandmixing;Moldingandpackaging;Flaming

VerticalsplitmoldcommonlyusedforlipstickformulationPlasticormetalverticalsplitmoldsareused,seetheFigure.Theirinnersurfacemustbesmoothtoproducenon-stickingsticks.Iftheyaremadeofmetal,theycanbepreviouslyheatedandusedwhilehot.Itmayalsobehelpfultogreasethemoldwithoilbeforemolding.FormulationofLipMakeupProducts37Molding:Pigmentpremilling;Meltingandmixing;Moldingandpackaging;Flaming

Thelaststepoflipstickformulationwheresticksarepassedthroughflame,e.g.,usingagasburner,toproduceaglossyfinishtolipsticks(seeFigure).Theflamesareadjustedtoalevelhotenoughtojustmeltthesurfaceofthestick.Lipsticksaretypicallyheldandtwistedintheflameforuptoasecondandthenremovedtoavoidmeltingandlosingshape.Finally,thecapsareputonthelipstickholderandarelabeled.FormulationofLipMakeupProducts38Molding:Pigmentpremilling;Meltingandmixing;Moldingandpackaging;Flaming

FlamingofalipstickMinimizationofairincorporationAirinthebulkisdifficulttoremoveandwillleadtounsightlypinholesinthestickduringmolding,resultinginslowproductionandincreasedrejectionrate.Minimalizedbyavoidingovermixingofthemixandrelativelyslowbutstilluninterruptedfilling.FormulationofLipMakeupProducts39Molding:Pigmentpremilling;Meltingandmixing;Moldingandpackaging;Flaming

FormulationofLipsticksbyMoldingtechniqueFormulationofLipMakeupProducts40Molding:Pigmentpremilling;Meltingandmixing;Moldingandpackaging;Flaming

FullyAutomaticLipstickProductionLineMostmodernlipsticksareproducedonautomaticlipstickmachines.Lipbalmsaretypicallyformulatedusingabasesimilartothatoflipsticks(i.e.,mixtureofwaxesandoils).However,insteadofpigments,theycontainadditionalmoisturizers,sunscreens,orotheractiveingredients.Lipbalmsinastickformareusuallyformulatedwiththemoldingtechnique.However,themeltedandhomogenousmixturecanbedirectlypouredintothefinallipbalmcontainers,whichmaybeplastictubes,pots,ormetaltins.Lipbalmsaretypicallynotsubjecttoflaming.Sometimes,thetipofthelipbalmsisflamedtoremoveanyholesthatmaybepresentaftermoldingandprovideashinysurfacetothestick’stip.FormulationofLipMakeupProducts41VariationsfortheMoldingTechnique1#:MoldingwithoutflamingLiplinersintheformofpencilscanalsobemadeviamolding.Inthiscase,themeltedmixisinjecteddirectlyintothehollowbarrelsusingasyringe.Thetipofthesyringecanbestuckintooneendofthepencilandthemeltedandstillhotmixcanbeslowlyinjectedintothebarrelwithoutinterruption.Thepencilisfilledcompletelywhenthefillingstartsdrippingattheotherendofthepencil.Afterinjecting,thepencilshouldbeheldhorizontallytoavoiddripping.Theproductcanbeplacedintoarefrigeratoruntilthefillingsolidifies.Beforeuse,thepencilshouldbesharpened.FormulationofLipMakeupProducts42VariationsfortheMoldingTechnique1#:MoldingwithoutflamingLipglossescontaininglargeramountofoilsandsignificantlylowerviscosity.Iftheycontainwaxes,meltingisstillnecessarytomixtheingredients.Therefore,theywillalsobeformulatedviamolding.Lipglossesthatdonotcontainwaxesorotheringredientsthatshouldbemeltedcanbeproducedbysimplymixingtheingredients.Whenahomogenousmixtureofthecomponentsisobtained,itcanbetransferredintoafinalcontainer,typicallyintoavialusingapipetteorsyringe.Althoughmeltingisnotnecessary,gentlewarmingmaybeneededforeasierpackaging.FormulationofLipMakeupProducts43VariationsfortheMoldingTechnique2#:SimplemixingwithoutheatingLiplinersandsomelipglossesareavailableinpencilform,canbeformulatedbyextrusion.TheFiguredepictsthemainpartsofanextruder.FormulationofLipMakeupProducts44VariationsfortheMoldingTechnique3#:ExtrusionThetypicalquality-relatedissues:(a)

Aeration,(b)Laddering,(c)Chipping,(d)Deformation,(e)Cratering,(f)Streaking,(g)Sweating,(h)Mushyfailure,(i)Seams,Bleeding,andPoorpay-off.TYPICALQUALITYPROBLEMSOFLIPMAKEUPPRODUCTS45Parameterscommonlytested:breakstrength,hardness,meltingpoint,softeningpoint,colormatching,colorbrightnessandstreakiness,pay-offandglide,rigidity,viscosity,andpH.Therangeofacceptanceandotherlimitingfactorsareusuallydeterminedbytheindividualmanufacturers.EVALUATIONOFLIPMAKEUPPRODUCTS46QualityParametersGenerallyTestedQualityParametersGenerallyTestedEVALUATIONOFLIPMAKEUPPRODUCTS47BreakstrengthtestingofalipstickBreakStrengthQualityParametersGenerallyTestedEVALUATIONOFLIPMAKEUPPRODUCTS48RigiditytestingofaliplinerpencilRigidityofLipLinerPencilsandLipGlossPencilsQualityParametersGenerallyTestedEVALUATIONOFLIPMAKEUPPRODUCTS49ColorMatchingTheprocesswhendispersedpigmentsandthefinishedproductarecomparedtoapreviouslyapprovedstandardcolor.Itisessentialtoproducethesameshadeofalipstickeverytimeacompanymanufacturesit.Thetestcanbedonevisuallyorusingspectrophotometersthatprovidequantitativeinformationontheshade.Ifdonevisually,thetestingenvironmentandlightingshouldbestandardizedsincemanyartificiallightsourcesmightdistortthecolorseen.QualityParametersGenerallyTestedEVALUATIONOFLIPMAKEUPPRODUCTS50ColorBrightnessandStreakinessEvaluatedvisually,andusingaspectrophotometerorcolorimeter.Spectrophotometersandcolorimetersprovidequantitativeinformationonthecolor;therefore,theycanidentifythematchwiththepreviousbatches.Coloronanapplicationsurfacecanbeevaluatedbyimageanalysis.Withthistechnique,itispossibletostudytheskinareasofvarioussizes,ta