diff --git a/rtdata/languages/default b/rtdata/languages/default
index f576937c5..c77da3fbf 100644
--- a/rtdata/languages/default
+++ b/rtdata/languages/default
@@ -1092,6 +1092,7 @@ HISTORY_MSG_852;Local - Target Gray
 HISTORY_MSG_853;Local - Detail
 HISTORY_MSG_854;Local - Scope encoding log
 HISTORY_MSG_855;Local - Entire image
+HISTORY_MSG_856;Local - Base log
 HISTORY_MSG_CLAMPOOG;Clip out-of-gamut colors
 HISTORY_MSG_COLORTONING_LABGRID_VALUE;CT - Color correction
 HISTORY_MSG_COLORTONING_LABREGION_AB;CT - Color correction
@@ -2169,6 +2170,7 @@ TP_LOCALLAB_AUTOGRAY;Automatic
 TP_LOCALLAB_AVOID;Avoid color shift
 TP_LOCALLAB_BALAN;Balance deltaE ab-L
 TP_LOCALLAB_BALANEXP;PDE balance
+TP_LOCALLAB_BASELOG;Logarithm base
 TP_LOCALLAB_BILATERAL;Bilateral filter
 TP_LOCALLAB_BLACK_EV;Black Ev
 TP_LOCALLAB_BLENDMASKCOL;Blend
diff --git a/rtengine/iplocallab.cc b/rtengine/iplocallab.cc
index 8b2b9a319..9b1bffec8 100644
--- a/rtengine/iplocallab.cc
+++ b/rtengine/iplocallab.cc
@@ -410,6 +410,7 @@ struct local_params {
     int sensilog;
     bool Autogray;
     bool autocompute;
+    float baselog;
 
 
 };
@@ -880,6 +881,7 @@ static void calcLocalParams(int sp, int oW, int oH, const LocallabParams& locall
     lp.sensilog = locallab.spots.at(sp).sensilog;
     lp.Autogray = locallab.spots.at(sp).Autogray;
     lp.autocompute = locallab.spots.at(sp).autocompute;
+    lp.baselog = (float) locallab.spots.at(sp).baselog;
 
     lp.deltaem = locallab.spots.at(sp).deltae;
     lp.scalereti = scaleret;
@@ -1262,14 +1264,16 @@ float find_gray(float source_gray, float target_gray)
 // https://github.com/ampas/aces-dev
 // (as seen on pixls.us)
 void ImProcFunctions::log_encode(Imagefloat *rgb, struct local_params & lp, float scale, bool multiThread)
-{
-    //small adaptations to local adjustements J.Desmis 12 2019
+{   /* J.Desmis 12 2019
+        small adaptations to local adjustements
+        replace log2 by log(lp.baselog) allows diferentiation between low and high lights
+    */
     BENCHFUN
     const float gray = lp.sourcegray / 100.f;
     const float shadows_range = lp.blackev;
     const float dynamic_range = lp.whiteev - lp.blackev;
     const float noise = pow_F(2.f, -16.f);
-    const float log2 = xlogf(2.f);
+    const float log2 = xlogf(lp.baselog);
     const float b = lp.targetgray > 1 && lp.targetgray < 100 && dynamic_range > 0 ? find_gray(std::abs(lp.blackev) / dynamic_range, lp.targetgray / 100.f) : 0.f;
     const float linbase = max(b, 0.f);
     TMatrix ws = ICCStore::getInstance()->workingSpaceMatrix(params->icm.workingProfile);
diff --git a/rtengine/procevents.h b/rtengine/procevents.h
index 1bbec24bd..49eea0099 100644
--- a/rtengine/procevents.h
+++ b/rtengine/procevents.h
@@ -881,6 +881,7 @@ enum ProcEventCode {
     Evlocallabdetail = 852,
     Evlocallabsensilog = 853,
     Evlocallabfullimage = 854,
+    Evlocallabbaselog = 855,
     NUMOFEVENTS
 };
 
diff --git a/rtengine/procparams.cc b/rtengine/procparams.cc
index 7c84daa7c..2e57b4929 100644
--- a/rtengine/procparams.cc
+++ b/rtengine/procparams.cc
@@ -2778,7 +2778,8 @@ LocallabParams::LocallabSpot::LocallabSpot() :
     blackEv(-5.0),
     whiteEv(10.0),
     detail(1),
-    sensilog(50)
+    sensilog(50),
+    baselog(2.)
 
 {
 }
@@ -3169,7 +3170,8 @@ bool LocallabParams::LocallabSpot::operator ==(const LocallabSpot& other) const
         && blackEv == other.blackEv
         && whiteEv == other.whiteEv
         && detail == other.detail
-        && sensilog == other.sensilog;
+        && sensilog == other.sensilog
+        && baselog == other.baselog;
 
 }
 
@@ -4528,6 +4530,7 @@ int ProcParams::save(const Glib::ustring& fname, const Glib::ustring& fname2, bo
                 saveToKeyfile(!pedited || pedited->locallab.spots.at(i).whiteEv, "Locallab", "WhiteEv_" + std::to_string(i), spot.whiteEv, keyFile);
                 saveToKeyfile(!pedited || pedited->locallab.spots.at(i).detail, "Locallab", "Detail_" + std::to_string(i), spot.detail, keyFile);
                 saveToKeyfile(!pedited || pedited->locallab.spots.at(i).sensilog, "Locallab", "Sensilog_" + std::to_string(i), spot.sensilog, keyFile);
+                saveToKeyfile(!pedited || pedited->locallab.spots.at(i).baselog, "Locallab", "Baselog_" + std::to_string(i), spot.baselog, keyFile);
 
             }
         }
@@ -6051,6 +6054,7 @@ int ProcParams::load(const Glib::ustring& fname, ParamsEdited* pedited)
                 assignFromKeyfile(keyFile, "Locallab", "WhiteEv_" + std::to_string(i), pedited, spot.whiteEv, spotEdited.whiteEv);
                 assignFromKeyfile(keyFile, "Locallab", "Detail_" + std::to_string(i), pedited, spot.detail, spotEdited.detail);
                 assignFromKeyfile(keyFile, "Locallab", "Sensilog_" + std::to_string(i), pedited, spot.sensilog, spotEdited.sensilog);
+                assignFromKeyfile(keyFile, "Locallab", "Baselog_" + std::to_string(i), pedited, spot.baselog, spotEdited.baselog);
 
 
                 locallab.spots.at(i) = spot;
diff --git a/rtengine/procparams.h b/rtengine/procparams.h
index 28f54cd9d..cf6efacae 100644
--- a/rtengine/procparams.h
+++ b/rtengine/procparams.h
@@ -1323,6 +1323,7 @@ struct LocallabParams {
         double whiteEv;
         int detail;
         int sensilog;
+        double baselog;
 
 
         LocallabSpot();
diff --git a/rtengine/refreshmap.cc b/rtengine/refreshmap.cc
index d5e347bae..702816312 100644
--- a/rtengine/refreshmap.cc
+++ b/rtengine/refreshmap.cc
@@ -884,7 +884,8 @@ int refreshmap[rtengine::NUMOFEVENTS] = {
     LUMINANCECURVE,          //EvlocallabtargetGray
     LUMINANCECURVE,          //Evlocallabdetail
     LUMINANCECURVE,          //Evlocallabsensilog
-    AUTOEXP                  //Evlocallabfullimage
+    AUTOEXP,                  //Evlocallabfullimage
+    LUMINANCECURVE          //Evlocallabbaselog
 
 };
 
diff --git a/rtgui/locallab.cc b/rtgui/locallab.cc
index cc651a0b3..68218a4c1 100644
--- a/rtgui/locallab.cc
+++ b/rtgui/locallab.cc
@@ -604,6 +604,7 @@ blackEv(Gtk::manage(new Adjuster(M("TP_LOCALLAB_BLACK_EV"), -16.0, 0.0, 0.1, -5.
 whiteEv(Gtk::manage(new Adjuster(M("TP_LOCALLAB_WHITE_EV"), 0.0, 32.0, 0.1, 10.0))),
 detail(Gtk::manage(new Adjuster(M("TP_LOCALLAB_DETAIL"), 0, 5, 1, 1))),
 sensilog(Gtk::manage(new Adjuster(M("TP_LOCALLAB_SENSILOG"), 0, 100, 1, 50))),
+baselog(Gtk::manage(new Adjuster(M("TP_LOCALLAB_BASELOG"), 1.3, 8., 0.05, 2., Gtk::manage(new RTImage("circle-black-small.png")), Gtk::manage(new RTImage("circle-white-small.png"))))), 
 
 // ButtonCheck widgets
 // Color & Light
@@ -3448,6 +3449,7 @@ pe(nullptr)
     targetGray->setAdjusterListener(this);
     detail->setAdjusterListener(this);
     sensilog->setAdjusterListener(this);
+    baselog->setAdjusterListener(this);
 
     whiteEv->setLogScale(16, 0);
     blackEv->setLogScale(2, -8);
@@ -3474,6 +3476,7 @@ pe(nullptr)
     logBox->pack_start(*logFrame);
     logBox->pack_start(*targetGray);
     logBox->pack_start(*detail);
+    logBox->pack_start(*baselog);
     logBox->pack_start(*sensilog);
 
 
@@ -5051,6 +5054,7 @@ void Locallab::write(rtengine::procparams::ProcParams* pp, ParamsEdited* pedited
                     pp->locallab.spots.at(pp->locallab.selspot).targetGray = targetGray->getValue();
                     pp->locallab.spots.at(pp->locallab.selspot).detail = detail->getIntValue();
                     pp->locallab.spots.at(pp->locallab.selspot).sensilog = sensilog->getIntValue();
+                    pp->locallab.spots.at(pp->locallab.selspot).baselog = baselog->getValue();
 
                 }
 
@@ -5430,6 +5434,7 @@ void Locallab::write(rtengine::procparams::ProcParams* pp, ParamsEdited* pedited
                         pe->locallab.spots.at(pp->locallab.selspot).targetGray = pe->locallab.spots.at(pp->locallab.selspot).targetGray || targetGray->getEditedState();
                         pe->locallab.spots.at(pp->locallab.selspot).detail = pe->locallab.spots.at(pp->locallab.selspot).detail || detail->getEditedState();
                         pe->locallab.spots.at(pp->locallab.selspot).sensilog = pe->locallab.spots.at(pp->locallab.selspot).sensilog || sensilog->getEditedState();
+                        pe->locallab.spots.at(pp->locallab.selspot).baselog = pe->locallab.spots.at(pp->locallab.selspot).baselog || baselog->getEditedState();
 
                     }
                 }
@@ -5810,6 +5815,7 @@ void Locallab::write(rtengine::procparams::ProcParams* pp, ParamsEdited* pedited
                         pedited->locallab.spots.at(pp->locallab.selspot).targetGray = pedited->locallab.spots.at(pp->locallab.selspot).targetGray || targetGray->getEditedState();
                         pedited->locallab.spots.at(pp->locallab.selspot).detail = pedited->locallab.spots.at(pp->locallab.selspot).detail || detail->getEditedState();
                         pedited->locallab.spots.at(pp->locallab.selspot).sensilog = pedited->locallab.spots.at(pp->locallab.selspot).sensilog || sensilog->getEditedState();
+                        pedited->locallab.spots.at(pp->locallab.selspot).baselog = pedited->locallab.spots.at(pp->locallab.selspot).baselog || baselog->getEditedState();
 
                     }
                 }
@@ -8253,6 +8259,7 @@ void Locallab::setDefaults(const rtengine::procparams::ProcParams * defParams, c
     targetGray->setDefault((double)defSpot->targetGray);
     detail->setDefault((double)defSpot->detail);
     sensilog->setDefault((double)defSpot->sensilog);
+    baselog->setDefault((double)defSpot->baselog);
 
     // Set default edited states for adjusters and threshold adjusters
     if (!pedited) {
@@ -8482,6 +8489,7 @@ void Locallab::setDefaults(const rtengine::procparams::ProcParams * defParams, c
         targetGray->setDefaultEditedState(Irrelevant);
         detail->setDefaultEditedState(Irrelevant);
         sensilog->setDefaultEditedState(Irrelevant);
+        baselog->setDefaultEditedState(Irrelevant);
 
     } else {
         const LocallabParamsEdited::LocallabSpotEdited* defSpotState = new LocallabParamsEdited::LocallabSpotEdited(true);
@@ -8717,6 +8725,7 @@ void Locallab::setDefaults(const rtengine::procparams::ProcParams * defParams, c
         targetGray->setDefaultEditedState(defSpotState->targetGray ? Edited : UnEdited);
         detail->setDefaultEditedState(defSpotState->detail ? Edited : UnEdited);
         sensilog->setDefaultEditedState(defSpotState->sensilog ? Edited : UnEdited);
+        baselog->setDefaultEditedState(defSpotState->baselog ? Edited : UnEdited);
 
     }
 }
@@ -10074,6 +10083,12 @@ void Locallab::adjusterChanged(Adjuster * a, double newval)
             }
         }
 
+        if (a == baselog) {
+            if (listener) {
+                listener->panelChanged(Evlocallabbaselog, baselog->getTextValue());
+            }
+        }
+
     }
 
 }
@@ -10330,6 +10345,7 @@ void Locallab::setBatchMode(bool batchMode)
     targetGray->showEditedCB();
     detail->showEditedCB();
     sensilog->showEditedCB();
+    baselog->showEditedCB();
 
 
     // Set batch mode for comboBoxText
@@ -11440,6 +11456,7 @@ void Locallab::updateLocallabGUI(const rtengine::procparams::ProcParams* pp, con
         targetGray->setValue(pp->locallab.spots.at(index).targetGray);
         detail->setValue(pp->locallab.spots.at(index).detail);
         sensilog->setValue(pp->locallab.spots.at(index).sensilog);
+        baselog->setValue(pp->locallab.spots.at(index).baselog);
 
         if (pedited) {
             if (index < (int)pedited->locallab.spots.size()) {
@@ -11881,6 +11898,7 @@ void Locallab::updateLocallabGUI(const rtengine::procparams::ProcParams* pp, con
                 targetGray->setEditedState(spotState->targetGray ? Edited : UnEdited);
                 detail->setEditedState(spotState->detail ? Edited : UnEdited);
                 sensilog->setEditedState(spotState->sensilog ? Edited : UnEdited);
+                baselog->setEditedState(spotState->baselog ? Edited : UnEdited);
 
             }
         }
diff --git a/rtgui/locallab.h b/rtgui/locallab.h
index dba2a6092..799eeafa6 100644
--- a/rtgui/locallab.h
+++ b/rtgui/locallab.h
@@ -388,6 +388,7 @@ private:
     Adjuster* const whiteEv;
     Adjuster* const detail;
     Adjuster* const sensilog;
+    Adjuster* const baselog;
 
     // ButtonCheck widgets
     // Color & Light
diff --git a/rtgui/paramsedited.cc b/rtgui/paramsedited.cc
index 85655dc6b..23b4d76e5 100644
--- a/rtgui/paramsedited.cc
+++ b/rtgui/paramsedited.cc
@@ -1320,6 +1320,7 @@ void ParamsEdited::initFrom(const std::vector<rtengine::procparams::ProcParams>&
                 locallab.spots.at(j).whiteEv = locallab.spots.at(j).whiteEv && pSpot.whiteEv == otherSpot.whiteEv;
                 locallab.spots.at(j).detail = locallab.spots.at(j).detail && pSpot.detail == otherSpot.detail;
                 locallab.spots.at(j).sensilog = locallab.spots.at(j).sensilog && pSpot.sensilog == otherSpot.sensilog;
+                locallab.spots.at(j).baselog = locallab.spots.at(j).baselog && pSpot.baselog == otherSpot.baselog;
 
             }
         }
@@ -4191,6 +4192,10 @@ void ParamsEdited::combine(rtengine::procparams::ProcParams& toEdit, const rteng
             toEdit.locallab.spots.at(i).sensilog = mods.locallab.spots.at(i).sensilog;
         }
 
+        if (locallab.spots.at(i).baselog) {
+            toEdit.locallab.spots.at(i).baselog = mods.locallab.spots.at(i).baselog;
+        }
+
 //        if (locallab.spots.at(i).autogray) {
 //            toEdit.locallab.spots.at(i).autogray = mods.locallab.spots.at(i).autogray;
  //       }
@@ -5535,7 +5540,8 @@ LocallabParamsEdited::LocallabSpotEdited::LocallabSpotEdited(bool v) :
     blackEv(v),
     whiteEv(v),
     detail(v),
-    sensilog(v)
+    sensilog(v),
+    baselog(v)
 
 {
 }
@@ -5912,6 +5918,7 @@ void LocallabParamsEdited::LocallabSpotEdited::set(bool v)
     whiteEv = v;
     detail = v;
     sensilog = v;
+    baselog = v;
 
 }
 
diff --git a/rtgui/paramsedited.h b/rtgui/paramsedited.h
index 7268dc233..9b227f3f7 100644
--- a/rtgui/paramsedited.h
+++ b/rtgui/paramsedited.h
@@ -750,6 +750,7 @@ public:
         bool whiteEv;
         bool detail;
         bool sensilog;
+        bool baselog;
 
         LocallabSpotEdited(bool v);