diff --git a/rtengine/dcrop.cc b/rtengine/dcrop.cc
index 8b8e5dba2..ddc360003 100644
--- a/rtengine/dcrop.cc
+++ b/rtengine/dcrop.cc
@@ -1100,65 +1100,8 @@ void Crop::update(int todo)
                 }
 
                 if (sp + 1u < params.locallab.spots.size()) {
-                    // do not do this for last spot as it is not needed anymore
+                    // do not copy for last spot as it is not needed anymore
                     lastorigCrop->CopyFrom(labnCrop);
-                    lllocalcurve2.clear();
-                    lclocalcurve2.clear();
-                    cllocalcurve2.clear();
-                    lightCurveloc2.clear();
-                    rgblocalcurve2.clear();
-                    cclocalcurve2.clear();
-                    exlocalcurve2.clear();
-                    lmasklocalcurve2.clear();
-                    lmaskexplocalcurve2.clear();
-                    lmaskSHlocalcurve2.clear();
-                    lmaskviblocalcurve2.clear();
-                    lmasktmlocalcurve2.clear();
-                    lmaskretilocalcurve2.clear();
-                    lmaskcblocalcurve2.clear();
-                    lmaskbllocalcurve2.clear();
-                    hltonecurveloc2.clear();
-                    shtonecurveloc2.clear();
-                    tonecurveloc2.clear();
-                    locRETgainCurve.Reset();
-                    locRETtransCurve.Reset();
-                    loclhCurve.Reset();
-                    lochhCurve.Reset();
-                    locccmasCurve.Reset();
-                    locllmasCurve.Reset();
-                    lochhmasCurve.Reset();
-                    lochhhmasCurve.Reset();
-                    locllmasexpCurve.Reset();
-                    locccmasexpCurve.Reset();
-                    lochhmasexpCurve.Reset();
-                    locllmasSHCurve.Reset();
-                    locccmasSHCurve.Reset();
-                    lochhmasSHCurve.Reset();
-                    locllmasvibCurve.Reset();
-                    locccmasvibCurve.Reset();
-                    lochhmasvibCurve.Reset();
-                    locllmascbCurve.Reset();
-                    locccmascbCurve.Reset();
-                    lochhmascbCurve.Reset();
-                    locllmasretiCurve.Reset();
-                    locccmasretiCurve.Reset();
-                    lochhmasretiCurve.Reset();
-                    locllmastmCurve.Reset();
-                    locccmastmCurve.Reset();
-                    lochhmastmCurve.Reset();
-                    locllmasblCurve.Reset();
-                    locccmasblCurve.Reset();
-                    lochhmasblCurve.Reset();
-                    locllmaslcCurve.Reset();
-                    locccmaslcCurve.Reset();
-                    lochhmaslcCurve.Reset();
-                    locwavCurve.Reset();
-                    loclevwavCurve.Reset();
-                    locconwavCurve.Reset();
-                    locconwavCurve.Reset();
-                    locwavCurveden.Reset();
-                    loclmasCurveblwav.Reset();
-                    loclmasCurvecolwav.Reset();
                 }
 
                 if (skip <= 2) {
diff --git a/rtengine/improccoordinator.cc b/rtengine/improccoordinator.cc
index 2221a53f3..52cf79203 100644
--- a/rtengine/improccoordinator.cc
+++ b/rtengine/improccoordinator.cc
@@ -1214,7 +1214,10 @@ void ImProcCoordinator::updatePreviewImage(int todo, bool panningRelatedChange)
                                   huerblu, chromarblu, lumarblu, huer, chromar, lumar, sobeler, lastsav, false, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                                   minCD, maxCD, mini, maxi, Tmean, Tsigma, Tmin, Tmax);
 
-                    lastorigimp->CopyFrom(nprevl);
+                    if (sp + 1u < params->locallab.spots.size()) {
+                        // do not copy for last spot as it is not needed anymore
+                        lastorigimp->CopyFrom(nprevl);
+                    }
 
                     // Save Locallab Retinex min/max for current spot
                     LocallabListener::locallabRetiMinMax retiMinMax;
@@ -1241,74 +1244,6 @@ void ImProcCoordinator::updatePreviewImage(int todo, bool panningRelatedChange)
                         locallref.at(sp).lumar = lumar;
                         locallref.at(sp).huer = huer;
                     }
-
-                    /*
-                    //very bad idea : it's the story of the cat biting its tail
-                    // brings big bugs..
-                                    //restore ref values
-                                    huerefs[sp] = huer;
-                                    chromarefs[sp] = chromar;
-                                    lumarefs[sp] = lumar ;
-                                    sobelrefs[sp] = sobeler;
-                    */
-                    lllocalcurve.clear();
-                    lclocalcurve.clear();
-                    cllocalcurve.clear();
-                    lightCurveloc.clear();
-                    cclocalcurve.clear();
-                    rgblocalcurve.clear();
-                    exlocalcurve.clear();
-                    lmasklocalcurve.clear();
-                    lmaskexplocalcurve.clear();
-                    lmaskSHlocalcurve.clear();
-                    lmaskviblocalcurve.clear();
-                    lmasktmlocalcurve.clear();
-                    lmaskretilocalcurve.clear();
-                    lmaskcblocalcurve.clear();
-                    lmaskbllocalcurve.clear();
-                    lmasklclocalcurve.clear();
-                    hltonecurveloc.clear();
-                    shtonecurveloc.clear();
-                    tonecurveloc.clear();
-                    locRETgainCurve.Reset();
-                    locRETtransCurve.Reset();
-                    loclhCurve.Reset();
-                    lochhCurve.Reset();
-                    locccmasCurve.Reset();
-                    locllmasCurve.Reset();
-                    lochhmasCurve.Reset();
-                    lochhhmasCurve.Reset();
-                    locllmasexpCurve.Reset();
-                    locccmasexpCurve.Reset();
-                    lochhmasexpCurve.Reset();
-                    locllmasSHCurve.Reset();
-                    locccmasSHCurve.Reset();
-                    lochhmasSHCurve.Reset();
-                    locllmasvibCurve.Reset();
-                    locccmasvibCurve.Reset();
-                    lochhmasvibCurve.Reset();
-                    locllmascbCurve.Reset();
-                    locccmascbCurve.Reset();
-                    lochhmascbCurve.Reset();
-                    locllmasretiCurve.Reset();
-                    locccmasretiCurve.Reset();
-                    lochhmasretiCurve.Reset();
-                    locllmastmCurve.Reset();
-                    locccmastmCurve.Reset();
-                    lochhmastmCurve.Reset();
-                    locllmasblCurve.Reset();
-                    locccmasblCurve.Reset();
-                    lochhmasblCurve.Reset();
-                    locllmaslcCurve.Reset();
-                    locccmaslcCurve.Reset();
-                    lochhmaslcCurve.Reset();
-                    locwavCurve.Reset();
-                    loclevwavCurve.Reset();
-                    locconwavCurve.Reset();
-                    locwavCurveden.Reset();
-                    locwavCurve.Reset();
-                    loclmasCurveblwav.Reset();
-                    loclmasCurvecolwav.Reset();
                 }
 
                 // Transmit Locallab reference values and Locallab Retinex min/max to LocallabListener
diff --git a/rtengine/simpleprocess.cc b/rtengine/simpleprocess.cc
index 4d31559b3..e28efb8c7 100644
--- a/rtengine/simpleprocess.cc
+++ b/rtengine/simpleprocess.cc
@@ -1296,26 +1296,6 @@ private:
                 } else {
                     ipf.calc_ref(sp, labView, labView, 0, 0, fw, fh, 1, huerefblu, chromarefblu, lumarefblu, huere, chromare, lumare, sobelre, avge, locwavCurveden, locwavdenutili);
                 }
-
-                // Clear local curves
-                lllocalcurve.clear();
-                lclocalcurve.clear();
-                cllocalcurve.clear();
-                cclocalcurve.clear();
-                rgblocalcurve.clear();
-                exlocalcurve.clear();
-                hltonecurveloc.clear();
-                lmasklocalcurve.clear();
-                lmaskexplocalcurve.clear();
-                lmaskSHlocalcurve.clear();
-                lmaskviblocalcurve.clear();
-                lmasktmlocalcurve.clear();
-                lmaskretilocalcurve.clear();
-                lmaskcblocalcurve.clear();
-                lmaskbllocalcurve.clear();
-                shtonecurveloc.clear();
-                tonecurveloc.clear();
-                lightCurveloc.clear();
             }
 
             t2.set();