diff --git a/rtengine/rawimage.cc b/rtengine/rawimage.cc
index de392623d..8d7292113 100644
--- a/rtengine/rawimage.cc
+++ b/rtengine/rawimage.cc
@@ -695,7 +695,7 @@ float** RawImage::compress_image(int frameNum, bool freeImage)
     } else if (colors == 1) {
         // Monochrome
         if (!allocation) {
-            allocation = new float[height * width];
+            allocation = new float[static_cast<unsigned long>(height) * static_cast<unsigned long>(width)];
             data = new float*[height];
 
             for (int i = 0; i < height; i++) {
@@ -704,7 +704,7 @@ float** RawImage::compress_image(int frameNum, bool freeImage)
         }
     } else {
         if (!allocation) {
-            allocation = new float[3 * height * width];
+            allocation = new float[3UL * static_cast<unsigned long>(height) * static_cast<unsigned long>(width)];
             data = new float*[height];
 
             for (int i = 0; i < height; i++) {