diff --git a/src/consts.cu b/src/consts.cu
index fc9d1b9..ed48441 100644
--- a/src/consts.cu
+++ b/src/consts.cu
@@ -52,4 +52,5 @@ __device__ float d_opacityK;
 __device__ float d_sigmoidShift;
 __device__ float d_sigmoidExp;
 __device__ int d_tfComboSelected;
+__device__ int d_tfComboSelectedColor;
 __device__ float d_opacityConst;
diff --git a/src/consts.h b/src/consts.h
index dcfa599..7d739a3 100644
--- a/src/consts.h
+++ b/src/consts.h
@@ -69,6 +69,7 @@ extern __device__ float d_sigmoidShift;
 extern __device__ float d_sigmoidExp;
 // combo box index
 extern __device__ int d_tfComboSelected;
+extern __device__ int d_tfComboSelectedColor;
 // constant opacity option
 extern __device__ float d_opacityConst;
 
diff --git a/src/gui/input/Widget.cpp b/src/gui/input/Widget.cpp
index 03f3a04..1dfd3ef 100644
--- a/src/gui/input/Widget.cpp
+++ b/src/gui/input/Widget.cpp
@@ -71,6 +71,21 @@ void Widget::tick(double fps) {
     }
     ImGui::EndCombo();
   }
+
+  // Same comments as above apply
+  const char* items2[] = {"Python-like", "BPR", "Greyscale", "..."};
+  if (ImGui::BeginCombo("ComboBox for color map", items2[this->tfComboSelectedColor]))
+  {
+    for (int n = 0; n < IM_ARRAYSIZE(items2); n++)
+    {
+      const bool is_selected = (this->tfComboSelectedColor == n);
+      if (ImGui::Selectable(items2[n], is_selected))
+        this->tfComboSelectedColor = n;
+      if (is_selected)
+        ImGui::SetItemDefaultFocus();
+    }
+    ImGui::EndCombo();
+  }
   ImGui::End();
 
   ImGui::Begin("Light Controls");
@@ -119,10 +134,12 @@ void Widget::copyToDevice() {
 
   cudaMemcpyToSymbol(&d_sigmoidShift, &this->sigmoidShift, sizeof(float));
   cudaMemcpyToSymbol(&d_sigmoidExp, &this->sigmoidExp, sizeof(float));
-  cudaMemcpyToSymbol(&d_tfComboSelected, &this->tfComboSelected, sizeof(float));
+  cudaMemcpyToSymbol(&d_tfComboSelected, &this->tfComboSelected, sizeof(int));
 
   this->opacityConstReal = std::pow(10.0f, (-5 + 0.05 * this->opacityConst));
   cudaMemcpyToSymbol(&d_opacityConst, &this->opacityConstReal, sizeof(float));
+
+  cudaMemcpyToSymbol(&d_tfComboSelectedColor, &this->tfComboSelectedColor, sizeof(int));
 }
 
 Widget::~Widget() {
diff --git a/src/gui/input/Widget.h b/src/gui/input/Widget.h
index c2fe991..ac2cbcd 100644
--- a/src/gui/input/Widget.h
+++ b/src/gui/input/Widget.h
@@ -19,6 +19,7 @@ public:
   char* fps;
 
   int tfComboSelected;
+  int tfComboSelectedColor;
   int opacityK;
   float opacityKReal;
   float sigmoidShift;
diff --git a/src/illumination/transferFunction.cu b/src/illumination/transferFunction.cu
index 0cb3271..060548a 100644
--- a/src/illumination/transferFunction.cu
+++ b/src/illumination/transferFunction.cu
@@ -40,17 +40,35 @@ __device__ float4 transferFunction(float density, const Vec3& grad, const Point3
   
   // --------------------------- Sample the volume ---------------------------
   // TODO: Somehow pick if to use temp of speed normalization ... or pass extremas as params.
-  float normDensity = (density - MIN_TEMP) / (MAX_TEMP - MIN_TEMP);
+  // float normDensity = (density - MIN_TEMP) / (MAX_TEMP - MIN_TEMP);
+  float normDensity = (density - 273) / (MAX_TEMP - MIN_TEMP)+16.f/21.f;  // Make zero match Celsius zero
+
   // float normDensity = (density - MIN_SPEED) / (MAX_SPEED - MIN_SPEED);
 
   normDensity = clamp(normDensity, 0.0f, 1.0f);
 
   // --------------------------- Map density to color ---------------------------
-  // TODO: Add a way to pick stops here
-  Color3 baseColor = colorMap(normDensity, d_stopsPythonLike, lenStopsPythonLike);
+  // Pick color map
+  Color3 baseColor;
+  switch (d_tfComboSelectedColor) {
+  case 0:
+    baseColor = colorMap(normDensity, d_stopsPythonLike, lenStopsPythonLike);
+    break;
+  
+  case 1:
+    baseColor = colorMap(normDensity, d_stopsBluePurleRed, lenStopsBluePurpleRed);
+    break;
 
-  // TODO: This is a Gui select element
-  // TODO: Add a way to pick different function for alpha
+  case 2:
+    baseColor = colorMap(normDensity, d_stopsGrayscale, lenStopsGrayscale);
+    break;
+
+  default:
+    baseColor = colorMap(normDensity, d_stopsPythonLike, lenStopsPythonLike);
+    break;
+  }
+
+  // Pick opacity function
   float alpha;
   switch (d_tfComboSelected) {
   case 0: