diff --git a/rtengine/LUT.h b/rtengine/LUT.h
index 965180c92..418f90a23 100644
--- a/rtengine/LUT.h
+++ b/rtengine/LUT.h
@@ -52,6 +52,8 @@
  *          LUTf stands for LUT<float>
  *          LUTi stands for LUT<int>
  *          LUTu stands for LUT<unsigned int>
+ *          LUTd stands for LUT<double>
+ *          LUTuc stands for LUT<unsigned char>
  */
 
 #ifndef LUT_H_
@@ -65,6 +67,7 @@
 #define LUTi LUT<int>
 #define LUTu LUT<unsigned int>
 #define LUTd LUT<double>
+#define LUTuc LUT<unsigned char>
 
 #include <cstring>
 #ifndef NDEBUG
diff --git a/rtengine/color.cc b/rtengine/color.cc
index faf8e358e..82eecb3eb 100644
--- a/rtengine/color.cc
+++ b/rtengine/color.cc
@@ -36,7 +36,7 @@ LUTf Color::cachef;
 LUTf Color::gamma2curve;
 
 LUTf Color::gammatab;
-unsigned char* Color::gammatabThumb = nullptr;
+LUTuc Color::gammatabThumb;
 LUTf Color::igammatab_srgb;
 LUTf Color::gammatab_srgb;
 //  LUTf Color::igammatab_709;
@@ -141,7 +141,7 @@ void Color::init ()
     cachef(maxindex, LUT_CLIP_BELOW);
     gamma2curve(maxindex, LUT_CLIP_BELOW | LUT_CLIP_ABOVE);
     gammatab(maxindex, 0);
-    gammatabThumb = new unsigned char[maxindex];
+    gammatabThumb(maxindex, 0);
 
     igammatab_srgb(maxindex, 0);
     gammatab_srgb(maxindex, 0);
@@ -163,20 +163,25 @@ void Color::init ()
 
 #ifdef _OPENMP
     #pragma omp parallel sections
-#endif // _OPENMP
+#endif
     {
 #ifdef _OPENMP
         #pragma omp section
 #endif
+        {
+            int i = 0;
+            int epsmaxint = eps_max;
 
-        for (int i = 0; i < maxindex; i++) {
-            if (i > eps_max) {
-                cachef[i] = 327.68 * std::cbrt((double)i / MAXVALF);
-            } else {
+            for (; i <= epsmaxint; i++)
+            {
                 cachef[i] = 327.68 * ((kappa * i / MAXVALF + 16.0) / 116.0);
             }
-        }
 
+            for(; i < maxindex; i++)
+            {
+                cachef[i] = 327.68 * std::cbrt((double)i / MAXVALF);
+            }
+        }
 #ifdef _OPENMP
         #pragma omp section
 #endif
@@ -293,7 +298,6 @@ void Color::init ()
             gammatab_26_11[i] = 65535.0 * gamma26_11 (i / 65535.0);
         }
 
-//gammatab_145_3
 #ifdef _OPENMP
         #pragma omp section
 #endif
@@ -335,10 +339,6 @@ void Color::cleanup ()
     if (linearGammaTRC) {
         cmsFreeToneCurve(linearGammaTRC);
     }
-
-    if(gammatabThumb) {
-        delete [] gammatabThumb;
-    }
 }
 
 void Color::rgb2hsl(float r, float g, float b, float &h, float &s, float &l)
diff --git a/rtengine/color.h b/rtengine/color.h
index 89c34c3ca..3f78692d8 100644
--- a/rtengine/color.h
+++ b/rtengine/color.h
@@ -148,7 +148,7 @@ public:
 
     // look-up tables for the simple exponential gamma
     static LUTf gammatab;
-    static unsigned char *gammatabThumb; // for thumbnails
+    static LUTuc gammatabThumb; // for thumbnails
 
 
     static void init ();
diff --git a/rtengine/init.cc b/rtengine/init.cc
index 4bba74a43..d2509b620 100644
--- a/rtengine/init.cc
+++ b/rtengine/init.cc
@@ -29,8 +29,6 @@
 #include "rtthumbnail.h"
 #include "../rtgui/profilestore.h"
 #include "../rtgui/threadutils.h"
-#define BENCHMARK
-#include "StopWatch.h"
 
 namespace rtengine
 {
@@ -41,7 +39,6 @@ MyMutex* lcmsMutex = NULL;
 
 int init (const Settings* s, Glib::ustring baseDir, Glib::ustring userSettingsDir)
 {
-    BENCHFUN
     settings = s;
     iccStore->init (s->iccDirectory, baseDir + "/iccprofiles");
     iccStore->findDefaultMonitorProfile();
diff --git a/rtengine/ipretinex.cc b/rtengine/ipretinex.cc
index 090841a9e..1cd1d56e1 100644
--- a/rtengine/ipretinex.cc
+++ b/rtengine/ipretinex.cc
@@ -45,7 +45,7 @@
 #include "rawimagesource.h"
 #include "improcfun.h"
 #include "opthelper.h"
-#define BENCHMARK
+//#define BENCHMARK
 #include "StopWatch.h"
 
 #define MAX_RETINEX_SCALES   8
diff --git a/rtengine/previewimage.cc b/rtengine/previewimage.cc
index 5f7ea8ad6..f9f6c12a1 100644
--- a/rtengine/previewimage.cc
+++ b/rtengine/previewimage.cc
@@ -23,7 +23,6 @@
 #include "iimage.h"
 #include "rtthumbnail.h"
 #include "rawimagesource.h"
-#include "StopWatch.h"
 
 using namespace rtengine;
 using namespace procparams;
@@ -144,9 +143,7 @@ PreviewImage::PreviewImage (const Glib::ustring &fname, const Glib::ustring &ext
             rawImage.getImage (wb, TR_NONE, image, pp, params.toneCurve, params.icm, params.raw);
             output = new Image8(fw, fh);
             rawImage.convertColorSpace(image, params.icm, wb);
-            StopWatch Stop1("inspector loop");
             #pragma omp parallel for schedule(dynamic, 10)
-
             for (int i = 0; i < fh; ++i)
                 for (int j = 0; j < fw; ++j) {
                     image->r(i, j) = Color::gamma2curve[image->r(i, j)];
@@ -154,7 +151,6 @@ PreviewImage::PreviewImage (const Glib::ustring &fname, const Glib::ustring &ext
                     image->b(i, j) = Color::gamma2curve[image->b(i, j)];
                 }
 
-            Stop1.stop();
 
             image->resizeImgTo<Image8>(fw, fh, TI_Nearest, output);
             data = output->getData();