diff --git a/ApplicationLibCode/Application/RiaPreferencesSummary.cpp b/ApplicationLibCode/Application/RiaPreferencesSummary.cpp
index 82b228e174..0a53be9110 100644
--- a/ApplicationLibCode/Application/RiaPreferencesSummary.cpp
+++ b/ApplicationLibCode/Application/RiaPreferencesSummary.cpp
@@ -21,6 +21,7 @@
 #include "PlotTemplateCommands/RicSummaryPlotTemplateTools.h"
 
 #include "RiaApplication.h"
+#include "RiaColorTables.h"
 #include "RiaPreferences.h"
 
 #include "PlotTemplates/RimPlotTemplateFileItem.h"
@@ -174,11 +175,13 @@ RiaPreferencesSummary::RiaPreferencesSummary()
     CAF_PDM_InitField( &m_curveColorByPhase, "curveColorByPhase", true, "Curve Color By Phase" );
     caf::PdmUiNativeCheckBoxEditor::configureFieldForEditor( &m_curveColorByPhase );
 
-    CAF_PDM_InitField( &m_appendHistoryVectorForDragDrop,
-                       "appendHistoryVectorForDragDrop",
-                       false,
-                       "Append History Vector for Drag/Drop" );
-    caf::PdmUiNativeCheckBoxEditor::configureFieldForEditor( &m_appendHistoryVectorForDragDrop );
+    CAF_PDM_InitField( &m_appendHistoryVectors, "appendHistoryVectorForDragDrop", false, "Append History Vectors" );
+    caf::PdmUiNativeCheckBoxEditor::configureFieldForEditor( &m_appendHistoryVectors );
+
+    CAF_PDM_InitField( &m_historyCurveContrastColor,
+                       "historyCurveContrastColor",
+                       RiaColorTables::historyCurveContrastColor(),
+                       "History Curve Contrast Color" );
 }
 
 //--------------------------------------------------------------------------------------------------
@@ -278,8 +281,10 @@ void RiaPreferencesSummary::appendItemsToPlottingGroup( caf::PdmUiOrdering& uiOr
     }
 
     uiOrdering.add( &m_defaultSummaryHistoryCurveStyle );
+
     uiOrdering.add( &m_curveColorByPhase );
-    uiOrdering.add( &m_appendHistoryVectorForDragDrop );
+    uiOrdering.add( &m_appendHistoryVectors );
+    uiOrdering.add( &m_historyCurveContrastColor, false );
 
     uiOrdering.add( &m_showSummaryTimeAsLongString );
 
@@ -356,9 +361,9 @@ bool RiaPreferencesSummary::colorCurvesByPhase() const
 //--------------------------------------------------------------------------------------------------
 ///
 //--------------------------------------------------------------------------------------------------
-bool RiaPreferencesSummary::appendHistoryVectorForDragDrop() const
+bool RiaPreferencesSummary::appendHistoryVectors() const
 {
-    return m_appendHistoryVectorForDragDrop();
+    return m_appendHistoryVectors();
 }
 
 //--------------------------------------------------------------------------------------------------
@@ -522,6 +527,14 @@ RiaDefines::RowCount RiaPreferencesSummary::defaultMultiPlotRowCount() const
     return m_defaultRowsPerPage();
 }
 
+//--------------------------------------------------------------------------------------------------
+///
+//--------------------------------------------------------------------------------------------------
+cvf::Color3f RiaPreferencesSummary::historyCurveContrastColor() const
+{
+    return m_historyCurveContrastColor();
+}
+
 //--------------------------------------------------------------------------------------------------
 ///
 //--------------------------------------------------------------------------------------------------
diff --git a/ApplicationLibCode/Application/RiaPreferencesSummary.h b/ApplicationLibCode/Application/RiaPreferencesSummary.h
index d8e75690dd..c4611e7f81 100644
--- a/ApplicationLibCode/Application/RiaPreferencesSummary.h
+++ b/ApplicationLibCode/Application/RiaPreferencesSummary.h
@@ -25,7 +25,11 @@
 
 #include "RiaDefines.h"
 
+// Include to make Pdm work for cvf::Color
+#include "cafPdmFieldCvfColor.h"
+
 #include <QString>
+
 #include <vector>
 
 //--------------------------------------------------------------------------------------------------
@@ -101,13 +105,15 @@ public:
     SummaryRestartFilesImportMode summaryEnsembleImportMode() const;
     QString                       defaultSummaryCurvesTextFilter() const;
     bool                          colorCurvesByPhase() const;
-    bool                          appendHistoryVectorForDragDrop() const;
+    bool                          appendHistoryVectors() const;
 
     SummaryHistoryCurveStyleMode defaultSummaryHistoryCurveStyle() const;
 
     RiaDefines::ColumnCount defaultMultiPlotColumnCount() const;
     RiaDefines::RowCount    defaultMultiPlotRowCount() const;
 
+    cvf::Color3f historyCurveContrastColor() const;
+
     void defineEditorAttribute( const caf::PdmFieldHandle* field,
                                 QString                    uiConfigName,
                                 caf::PdmUiEditorAttribute* attribute ) override;
@@ -130,7 +136,7 @@ private:
     caf::PdmField<QString>                          m_defaultSummaryCurvesTextFilter;
     caf::PdmField<SummaryHistoryCurveStyleModeType> m_defaultSummaryHistoryCurveStyle;
     caf::PdmField<bool>                             m_curveColorByPhase;
-    caf::PdmField<bool>                             m_appendHistoryVectorForDragDrop;
+    caf::PdmField<bool>                             m_appendHistoryVectors;
 
     caf::PdmField<bool> m_showSummaryTimeAsLongString;
     caf::PdmField<bool> m_useMultipleThreadsWhenLoadingSummaryCases;
@@ -145,4 +151,6 @@ private:
 
     caf::PdmField<ColumnCountEnum> m_defaultColumnCount;
     caf::PdmField<RowCountEnum>    m_defaultRowsPerPage;
+
+    caf::PdmField<cvf::Color3f> m_historyCurveContrastColor;
 };
diff --git a/ApplicationLibCode/Application/Tools/RiaColorTables.cpp b/ApplicationLibCode/Application/Tools/RiaColorTables.cpp
index 4522989faa..bdb9912a42 100644
--- a/ApplicationLibCode/Application/Tools/RiaColorTables.cpp
+++ b/ApplicationLibCode/Application/Tools/RiaColorTables.cpp
@@ -682,6 +682,16 @@ cvf::Color3f RiaColorTables::phaseColor( RiaDefines::PhaseType phase )
     }
 }
 
+//--------------------------------------------------------------------------------------------------
+///
+//--------------------------------------------------------------------------------------------------
+cvf::Color3f RiaColorTables::historyCurveContrastColor()
+{
+    auto unsignedColor = cvf::Color3ub( 248, 0, 170 ); // Magenta
+
+    return cvf::Color3f( unsignedColor );
+}
+
 //--------------------------------------------------------------------------------------------------
 ///
 //--------------------------------------------------------------------------------------------------
diff --git a/ApplicationLibCode/Application/Tools/RiaColorTables.h b/ApplicationLibCode/Application/Tools/RiaColorTables.h
index aa2db4a804..509447f787 100644
--- a/ApplicationLibCode/Application/Tools/RiaColorTables.h
+++ b/ApplicationLibCode/Application/Tools/RiaColorTables.h
@@ -81,6 +81,8 @@ public:
     static std::map<RiaDefines::PhaseType, caf::ColorTable> phaseColors();
     static cvf::Color3f                                     phaseColor( RiaDefines::PhaseType phase );
 
+    static cvf::Color3f historyCurveContrastColor();
+
 private:
     static std::vector<cvf::Color3ub> categoryColors();
     static std::vector<cvf::Color3ub> contrastCategoryColors();
diff --git a/ApplicationLibCode/Application/Tools/RiaColorTools.cpp b/ApplicationLibCode/Application/Tools/RiaColorTools.cpp
index 9c333b3423..04bdce0935 100644
--- a/ApplicationLibCode/Application/Tools/RiaColorTools.cpp
+++ b/ApplicationLibCode/Application/Tools/RiaColorTools.cpp
@@ -184,6 +184,26 @@ QColor RiaColorTools::blendQColors( const QColor& color1, const QColor& color2,
                    ( color1.blue() * weight1 + color2.blue() * weight2 ) / weightsum );
 }
 
+//--------------------------------------------------------------------------------------------------
+///
+//--------------------------------------------------------------------------------------------------
+cvf::Color3f RiaColorTools::makeLighter( const cvf::Color3f& color, float normalizedScalingFactor )
+{
+    auto qColor = toQColor( color );
+
+    double h = 0.0;
+    double s = 0.0;
+    double l = 0.0;
+    qColor.getHslF( &h, &s, &l );
+
+    l = l + ( 1.0 - l ) * normalizedScalingFactor;
+    l = std::min( 1.0, l );
+
+    qColor.setHslF( h, s, l );
+
+    return fromQColorTo3f( qColor );
+}
+
 //--------------------------------------------------------------------------------------------------
 ///
 //--------------------------------------------------------------------------------------------------
diff --git a/ApplicationLibCode/Application/Tools/RiaColorTools.h b/ApplicationLibCode/Application/Tools/RiaColorTools.h
index 2030cc233b..7c7b4e2ebe 100644
--- a/ApplicationLibCode/Application/Tools/RiaColorTools.h
+++ b/ApplicationLibCode/Application/Tools/RiaColorTools.h
@@ -49,6 +49,8 @@ public:
                   blendCvfColors( const cvf::Color3f& color1, const cvf::Color3f& color2, int weight1 = 1, int weight2 = 1 );
     static QColor blendQColors( const QColor& color1, const QColor& color2, int weight1 = 1, int weight2 = 1 );
 
+    static cvf::Color3f makeLighter( const cvf::Color3f& color1, float normalizedScalingFactor );
+
     // Factor > 1 increases saturation, a factor < 1 decreases saturation
     static QColor modifySaturation( const QColor& color, double factor );
 
diff --git a/ApplicationLibCode/Commands/PlotBuilderCommands/RicNewSummaryMultiPlotFromDataVectorFeature.cpp b/ApplicationLibCode/Commands/PlotBuilderCommands/RicNewSummaryMultiPlotFromDataVectorFeature.cpp
index 52382ff43b..cef51ed269 100644
--- a/ApplicationLibCode/Commands/PlotBuilderCommands/RicNewSummaryMultiPlotFromDataVectorFeature.cpp
+++ b/ApplicationLibCode/Commands/PlotBuilderCommands/RicNewSummaryMultiPlotFromDataVectorFeature.cpp
@@ -18,13 +18,16 @@
 
 #include "RicNewSummaryMultiPlotFromDataVectorFeature.h"
 
+#include "RiaPreferencesSummary.h"
 #include "RiaSummaryTools.h"
+
 #include "RimSummaryAddress.h"
 #include "RimSummaryPlot.h"
 
 #include "RicSummaryPlotBuilder.h"
 
 #include "RifEclipseSummaryAddress.h"
+#include "RifReaderEclipseSummary.h"
 
 #include "cafSelectionManagerTools.h"
 #include "cvfAssert.h"
@@ -97,6 +100,21 @@ void RicNewSummaryMultiPlotFromDataVectorFeature::onActionTriggered( bool isChec
         }
     }
 
+    if ( RiaPreferencesSummary::current()->appendHistoryVectors() )
+    {
+        auto sourceAddresses = eclipseAddresses;
+
+        for ( const auto& addr : sourceAddresses )
+        {
+            if ( !addr.isHistoryVector() )
+            {
+                auto historyAddr = addr;
+                historyAddr.setVectorName( addr.vectorName() + RifReaderEclipseSummary::historyIdentifier() );
+                eclipseAddresses.insert( historyAddr );
+            }
+        }
+    }
+
     auto newPlot = RicSummaryPlotBuilder::createPlot( eclipseAddresses, selectedCases, selectedEnsembles );
 
     std::vector<RimSummaryPlot*> plots{ newPlot };
diff --git a/ApplicationLibCode/Commands/SummaryPlotCommands/RicNewSummaryEnsembleCurveSetFeature.cpp b/ApplicationLibCode/Commands/SummaryPlotCommands/RicNewSummaryEnsembleCurveSetFeature.cpp
index 1e96749245..785ee478fb 100644
--- a/ApplicationLibCode/Commands/SummaryPlotCommands/RicNewSummaryEnsembleCurveSetFeature.cpp
+++ b/ApplicationLibCode/Commands/SummaryPlotCommands/RicNewSummaryEnsembleCurveSetFeature.cpp
@@ -34,6 +34,7 @@
 #include "RimProject.h"
 #include "RimSummaryCaseMainCollection.h"
 #include "RimSummaryCurve.h"
+#include "RimSummaryCurveAppearanceCalculator.h"
 #include "RimSummaryMultiPlot.h"
 #include "RimSummaryMultiPlotCollection.h"
 #include "RimSummaryPlot.h"
@@ -80,7 +81,10 @@ std::vector<RimEnsembleCurveSet*>
 
                 // Use same counting as RicNewSummaryCurveFeature::onActionTriggered
                 auto colorIndex = plot->singleColorCurveCount();
-                curveSet->setColor( RiaColorTables::summaryCurveDefaultPaletteColors().cycledColor3f( colorIndex ) );
+
+                curveSet->setColor(
+                    RimSummaryCurveAppearanceCalculator::computeTintedCurveColorForAddress( addr,
+                                                                                            static_cast<int>( colorIndex ) ) );
                 curveSet->legendConfig()->setColorLegend( RimRegularLegendConfig::mapToColorLegend(
                     RimEnsembleCurveSetColorManager::cycledEnsembleColorRange( static_cast<int>( colorIndex ) ) ) );
 
diff --git a/ApplicationLibCode/ProjectDataModel/Summary/RimEnsembleCurveSet.cpp b/ApplicationLibCode/ProjectDataModel/Summary/RimEnsembleCurveSet.cpp
index fa6f2fe872..0e971cb309 100644
--- a/ApplicationLibCode/ProjectDataModel/Summary/RimEnsembleCurveSet.cpp
+++ b/ApplicationLibCode/ProjectDataModel/Summary/RimEnsembleCurveSet.cpp
@@ -1702,7 +1702,14 @@ void RimEnsembleCurveSet::updateEnsembleCurves( const std::vector<RimSummaryCase
                 curve->setSummaryCaseY( sumCase );
                 curve->setSummaryAddressYAndApplyInterpolation( addr->address() );
                 curve->setResampling( m_resampling() );
-                curve->setLineThickness( 1 );
+
+                int lineThickness = 1;
+                if ( addr->address().isHistoryVector() )
+                {
+                    lineThickness = 2;
+                    curve->setCurveAppearanceFromCaseType();
+                }
+                curve->setLineThickness( lineThickness );
 
                 addCurve( curve );
 
diff --git a/ApplicationLibCode/ProjectDataModel/Summary/RimSummaryCurveAppearanceCalculator.cpp b/ApplicationLibCode/ProjectDataModel/Summary/RimSummaryCurveAppearanceCalculator.cpp
index ba878fef63..6539a32574 100644
--- a/ApplicationLibCode/ProjectDataModel/Summary/RimSummaryCurveAppearanceCalculator.cpp
+++ b/ApplicationLibCode/ProjectDataModel/Summary/RimSummaryCurveAppearanceCalculator.cpp
@@ -19,6 +19,7 @@
 #include "RimSummaryCurveAppearanceCalculator.h"
 
 #include "RiaColorTables.h"
+#include "RiaColorTools.h"
 #include "RiaPreferencesSummary.h"
 #include "RiaSummaryCurveDefinition.h"
 
@@ -387,6 +388,29 @@ cvf::Color3f RimSummaryCurveAppearanceCalculator::assignColorByPhase( const RifE
     return cycledNoneRGBBrColor( 0 );
 }
 
+//--------------------------------------------------------------------------------------------------
+///
+//--------------------------------------------------------------------------------------------------
+cvf::Color3f RimSummaryCurveAppearanceCalculator::computeTintedCurveColorForAddress( const RifEclipseSummaryAddress& address,
+                                                                                     int colorIndex )
+{
+    bool usePhaseColor = RiaPreferencesSummary::current()->colorCurvesByPhase();
+
+    cvf::Color3f curveColor;
+    if ( usePhaseColor )
+    {
+        curveColor = RimSummaryCurveAppearanceCalculator::assignColorByPhase( address );
+    }
+    else
+    {
+        curveColor = RiaColorTables::summaryCurveDefaultPaletteColors().cycledColor3f( colorIndex );
+    }
+
+    float scalingFactor = 0.25;
+    curveColor          = RiaColorTools::makeLighter( curveColor, scalingFactor );
+    return curveColor;
+}
+
 //--------------------------------------------------------------------------------------------------
 ///
 //--------------------------------------------------------------------------------------------------
diff --git a/ApplicationLibCode/ProjectDataModel/Summary/RimSummaryCurveAppearanceCalculator.h b/ApplicationLibCode/ProjectDataModel/Summary/RimSummaryCurveAppearanceCalculator.h
index a50b85ee35..61592713b5 100644
--- a/ApplicationLibCode/ProjectDataModel/Summary/RimSummaryCurveAppearanceCalculator.h
+++ b/ApplicationLibCode/ProjectDataModel/Summary/RimSummaryCurveAppearanceCalculator.h
@@ -61,8 +61,7 @@ public:
     void setupCurveLook( RimSummaryCurve* curve );
 
     static cvf::Color3f assignColorByPhase( const RifEclipseSummaryAddress& address );
-
-    void assignColorByPhase( RimSummaryCurve* curve, int colorIndex );
+    static cvf::Color3f computeTintedCurveColorForAddress( const RifEclipseSummaryAddress& address, int colorIndex );
 
     static cvf::Color3f                        cycledPaletteColor( int colorIndex );
     static cvf::Color3f                        cycledNoneRGBBrColor( int colorIndex );
@@ -84,6 +83,7 @@ private:
     float                                 gradient( size_t totalCount, int index );
 
     cvf::Color3f gradeColor( const cvf::Color3f& color, float factor );
+    void         assignColorByPhase( RimSummaryCurve* curve, int colorIndex );
 
     static std::set<std::string> getAllSummaryCaseNames();
     static std::set<std::string> getAllSummaryWellNames();
diff --git a/ApplicationLibCode/ProjectDataModel/Summary/RimSummaryPlot.cpp b/ApplicationLibCode/ProjectDataModel/Summary/RimSummaryPlot.cpp
index b4519fd1a0..cdbaaed199 100644
--- a/ApplicationLibCode/ProjectDataModel/Summary/RimSummaryPlot.cpp
+++ b/ApplicationLibCode/ProjectDataModel/Summary/RimSummaryPlot.cpp
@@ -776,20 +776,12 @@ void RimSummaryPlot::applyDefaultCurveAppearances()
     {
         if ( curveSet->colorMode() != RimEnsembleCurveSet::ColorMode::SINGLE_COLOR ) continue;
 
-        cvf::Color3f curveColor;
-        if ( RiaPreferencesSummary::current()->colorCurvesByPhase() )
-        {
-            curveColor = RimSummaryCurveAppearanceCalculator::assignColorByPhase( curveSet->summaryAddress() );
-        }
-        else
-        {
-            curveColor = RiaColorTables::summaryCurveDefaultPaletteColors().cycledColor3f( colorIndex++ );
-        }
+        cvf::Color3f curveColor =
+            RimSummaryCurveAppearanceCalculator::computeTintedCurveColorForAddress( curveSet->summaryAddress(),
+                                                                                    colorIndex++ );
 
-        int weightBaseColor = 10;
-        int weightWhite     = 25;
-
-        curveColor = RiaColorTools::blendCvfColors( curveColor, cvf::Color3f::WHITE, weightBaseColor, weightWhite );
+        auto adr = curveSet->summaryAddress();
+        if ( adr.isHistoryVector() ) curveColor = RiaPreferencesSummary::current()->historyCurveContrastColor();
 
         curveSet->setColor( curveColor );
     }
@@ -1991,17 +1983,6 @@ std::pair<int, std::vector<RimSummaryCurve*>> RimSummaryPlot::handleSummaryCaseD
     {
         const auto addr = curve->summaryAddressY();
         dataVectorMap[addr].insert( curve->summaryCaseY() );
-
-        if ( !addr.isHistoryVector() && RiaPreferencesSummary::current()->appendHistoryVectorForDragDrop() )
-        {
-            auto historyAddr = addr;
-            historyAddr.setVectorName( addr.vectorName() + RifReaderEclipseSummary::historyIdentifier() );
-
-            if ( summaryCase->summaryReader() && summaryCase->summaryReader()->hasAddress( historyAddr ) )
-            {
-                dataVectorMap[historyAddr].insert( curve->summaryCaseY() );
-            }
-        }
     }
 
     for ( const auto& [addr, cases] : dataVectorMap )
@@ -2083,7 +2064,7 @@ std::pair<int, std::vector<RimSummaryCurve*>>
         {
             newCurveDefsWithObjectNames[newCurveDef].insert( objectIdentifierString );
             const auto& addr = curveDef.summaryAddress();
-            if ( !addr.isHistoryVector() && RiaPreferencesSummary::current()->appendHistoryVectorForDragDrop() )
+            if ( !addr.isHistoryVector() && RiaPreferencesSummary::current()->appendHistoryVectors() )
             {
                 auto historyAddr = addr;
                 historyAddr.setVectorName( addr.vectorName() + RifReaderEclipseSummary::historyIdentifier() );
@@ -2133,7 +2114,7 @@ std::pair<int, std::vector<RimSummaryCurve*>> RimSummaryPlot::handleSummaryAddre
 
     std::vector<RifEclipseSummaryAddress> newCurveAddresses;
     newCurveAddresses.push_back( summaryAddr->address() );
-    if ( !summaryAddr->address().isHistoryVector() && RiaPreferencesSummary::current()->appendHistoryVectorForDragDrop() )
+    if ( !summaryAddr->address().isHistoryVector() && RiaPreferencesSummary::current()->appendHistoryVectors() )
     {
         auto historyAddr = summaryAddr->address();
         historyAddr.setVectorName( summaryAddr->address().vectorName() + RifReaderEclipseSummary::historyIdentifier() );
@@ -2294,18 +2275,15 @@ void RimSummaryPlot::addNewEnsembleCurveY( const RifEclipseSummaryAddress& addre
     curveSet->setSummaryCaseCollection( ensemble );
     curveSet->setSummaryAddress( address );
 
-    cvf::Color3f curveColor;
-    if ( RiaPreferencesSummary::current()->colorCurvesByPhase() )
-    {
-        auto basePhaseColor = RimSummaryCurveAppearanceCalculator::assignColorByPhase( curveSet->summaryAddress() );
+    cvf::Color3f curveColor =
+        RimSummaryCurveAppearanceCalculator::computeTintedCurveColorForAddress( curveSet->summaryAddress(),
+                                                                                static_cast<int>(
+                                                                                    ensembleCurveSetCollection()
+                                                                                        ->curveSetCount() ) );
+
+    auto adr = curveSet->summaryAddress();
+    if ( adr.isHistoryVector() ) curveColor = RiaPreferencesSummary::current()->historyCurveContrastColor();
 
-        curveColor = RiaColorTools::blendCvfColors( basePhaseColor, cvf::Color3f::WHITE, 1, 3 );
-    }
-    else
-    {
-        curveColor = RiaColorTables::summaryCurveDefaultPaletteColors().cycledColor3f(
-            ensembleCurveSetCollection()->curveSetCount() );
-    }
     curveSet->setColor( curveColor );
 
     ensembleCurveSetCollection()->addCurveSet( curveSet );