diff --git a/rtengine/clutstore.cc b/rtengine/clutstore.cc
index 533d1e89d..53adcc013 100644
--- a/rtengine/clutstore.cc
+++ b/rtengine/clutstore.cc
@@ -1,18 +1,22 @@
+#include <algorithm>
+
 #include "clutstore.h"
-#include "rt_math.h"
+
+#include "image16.h"
+#include "imagefloat.h"
 #include "stdimagesource.h"
 #include "../rtgui/options.h"
 
 namespace
 {
 
-std::unique_ptr<rtengine::Imagefloat> loadFile(
+std::unique_ptr<rtengine::Image16> loadFile(
     const Glib::ustring& filename,
     const Glib::ustring& working_color_space,
     unsigned int& clut_level
 )
 {
-    std::unique_ptr<rtengine::Imagefloat> result;
+    std::unique_ptr<rtengine::Image16> result;
 
     rtengine::StdImageSource img_src;
 
@@ -38,17 +42,19 @@ std::unique_ptr<rtengine::Imagefloat> loadFile(
 
     if (valid) {
         rtengine::ColorTemp curr_wb = img_src.getWB();
-        result = std::unique_ptr<rtengine::Imagefloat>(new rtengine::Imagefloat(fw, fh));
+        std::unique_ptr<rtengine::Imagefloat> img_float = std::unique_ptr<rtengine::Imagefloat>(new rtengine::Imagefloat(fw, fh));
         const PreviewProps pp(0, 0, fw, fh, 1);
 
         rtengine::procparams::ColorManagementParams icm;
         icm.working = working_color_space;
 
-        img_src.getImage(curr_wb, TR_NONE, result.get(), pp, rtengine::procparams::ToneCurveParams(), icm, rtengine::procparams::RAWParams());
+        img_src.getImage(curr_wb, TR_NONE, img_float.get(), pp, rtengine::procparams::ToneCurveParams(), icm, rtengine::procparams::RAWParams());
 
         if (!working_color_space.empty()) {
-            img_src.convertColorSpace(result.get(), icm, curr_wb);
+            img_src.convertColorSpace(img_float.get(), icm, curr_wb);
         }
+
+        result = std::unique_ptr<rtengine::Image16>(img_float->to16());
     }
 
     return result;
@@ -100,6 +106,8 @@ void rtengine::CLUT::splitClutFilename(
 
 rtengine::HaldCLUT::HaldCLUT() :
     clut_level(0),
+    flevel_minus_one(0.0f),
+    flevel_minus_two(0.0f),
     clut_profile("sRGB")
 {
 }
@@ -116,6 +124,9 @@ bool rtengine::HaldCLUT::load(const Glib::ustring& filename)
 
     if (clut_image) {
         clut_filename = filename;
+        clut_level *= clut_level;
+        flevel_minus_one = static_cast<float>(clut_level - 1) / 65535.0f;
+        flevel_minus_two = static_cast<float>(clut_level - 2);
         return true;
     }
 
@@ -139,10 +150,7 @@ Glib::ustring rtengine::HaldCLUT::getProfile() const
 
 void rtengine::HaldCLUT::getRGB(float r, float g, float b, float& out_r, float& out_g, float& out_b) const
 {
-    const unsigned int level = clut_level * clut_level;
-
-    const float flevel_minus_one = static_cast<float>(level - 1) / 65535.0f;
-    const float flevel_minus_two = static_cast<float>(level - 2);
+    const unsigned int level = clut_level; // This is important
 
     const unsigned int red = std::min(flevel_minus_two, r * flevel_minus_one);
     const unsigned int green = std::min(flevel_minus_two, g * flevel_minus_one);
diff --git a/rtengine/clutstore.h b/rtengine/clutstore.h
index ce8fd9627..b084c67fe 100644
--- a/rtengine/clutstore.h
+++ b/rtengine/clutstore.h
@@ -4,12 +4,13 @@
 
 #include <gtkmm.h>
 
-#include "imagefloat.h"
 #include "cache.h"
 
 namespace rtengine
 {
 
+class Image16;
+
 class CLUT
 {
 public:
@@ -50,8 +51,10 @@ public:
     void getRGB(float r, float g, float b, float& out_r, float& out_g, float& out_b) const;
 
 private:
-    std::unique_ptr<Imagefloat> clut_image;
+    std::unique_ptr<Image16> clut_image;
     unsigned int clut_level;
+    float flevel_minus_one;
+    float flevel_minus_two;
     Glib::ustring clut_filename;
     Glib::ustring clut_profile;
 };
diff --git a/rtengine/improcfun.cc b/rtengine/improcfun.cc
index 2732c567d..d61c79513 100644
--- a/rtengine/improcfun.cc
+++ b/rtengine/improcfun.cc
@@ -4337,8 +4337,6 @@ void ImProcFunctions::rgbProc (Imagefloat* working, LabImage* lab, PipetteBuffer
 
                 //Film Simulations
                 if ( colorLUT ) {
-                    MyTime start, stop;
-                    start.set();
                     for (int i = istart, ti = 0; i < tH; i++, ti++) {
                         for (int j = jstart, tj = 0; j < tW; j++, tj++) {
                             float &sourceR = rtemp[ti * TS + tj];
@@ -4377,8 +4375,6 @@ void ImProcFunctions::rgbProc (Imagefloat* working, LabImage* lab, PipetteBuffer
 
                         }
                     }
-                    stop.set();
-                    printf("Film simulation took %dus.\n", stop.etime(start));
                 }