diff --git a/rtengine/rtthumbnail.cc b/rtengine/rtthumbnail.cc
index 150582f57..1623ecfbf 100644
--- a/rtengine/rtthumbnail.cc
+++ b/rtengine/rtthumbnail.cc
@@ -62,15 +62,15 @@ bool checkRawImageThumb (const rtengine::RawImage& raw_image)
 void scale_colors (rtengine::RawImage *ri, float scale_mul[4], float cblack[4], bool multiThread)
 {
     DCraw::dcrawImage_t image = ri->get_image();
+    const int height = ri->get_iheight();
+    const int width = ri->get_iwidth();
+    const int top_margin = ri->get_topmargin();
+    const int left_margin = ri->get_leftmargin();
+    const int raw_width = ri->get_rawwidth();
+    const bool isFloat = ri->isFloat();
+    const float * const float_raw_image = ri->get_FloatRawImage();
 
     if (ri->isBayer()) {
-        const int height = ri->get_iheight();
-        const int width = ri->get_iwidth();
-        const bool isFloat = ri->isFloat();
-        const int top_margin = ri->get_topmargin();
-        const int left_margin = ri->get_leftmargin();
-        const int raw_width = ri->get_rawwidth();
-        const float * const float_raw_image = ri->get_FloatRawImage();
 #ifdef _OPENMP
         #pragma omp parallel for if(multiThread)
 #endif
@@ -110,14 +110,6 @@ void scale_colors (rtengine::RawImage *ri, float scale_mul[4], float cblack[4],
             }
         }
     } else if (ri->isXtrans()) {
-        const int height = ri->get_iheight();
-        const int width = ri->get_iwidth();
-        const bool isFloat = ri->isFloat();
-        const int top_margin = ri->get_topmargin();
-        const int left_margin = ri->get_leftmargin();
-        const int raw_width = ri->get_rawwidth();
-        const float * const float_raw_image = ri->get_FloatRawImage();
-
 #ifdef _OPENMP
         #pragma omp parallel for if(multiThread)
 #endif
@@ -157,6 +149,20 @@ void scale_colors (rtengine::RawImage *ri, float scale_mul[4], float cblack[4],
                 image[row * width + col][ccol] = rtengine::CLIP (val);
             }
         }
+    } else if (isFloat) {
+#ifdef _OPENMP
+        #pragma omp parallel for if(multiThread)
+#endif
+        for (int row = 0; row < height; ++row) {
+            for (int col = 0; col < width; ++col) {
+                for (int i = 0; i < ri->get_colors(); ++i) {
+                    float val = float_raw_image[(row + top_margin) * raw_width + col + left_margin + i];
+                    val -= cblack[i];
+                    val *= scale_mul[i];
+                    image[row * width + col][i] = val;
+                }
+            }
+        }
     } else {
         const int size = ri->get_iheight() * ri->get_iwidth();