diff --git a/hexrd/ui/hexrd_config.py b/hexrd/ui/hexrd_config.py
index 381797aee..5079057ce 100644
--- a/hexrd/ui/hexrd_config.py
+++ b/hexrd/ui/hexrd_config.py
@@ -888,8 +888,10 @@ def masked_images_dict(self):
         images_dict = self.images_dict
         for det, mask in self.raw_masks_dict.items():
             for name, img in images_dict.items():
+                if np.issubdtype(img.dtype, np.integer):
+                    img = img.astype(float)
                 if det == name:
-                    img[~mask] = 0
+                    img[~mask] = np.nan
 
         return images_dict