diff --git a/hexrd/ui/calibration/auto/powder_runner.py b/hexrd/ui/calibration/auto/powder_runner.py
index fc93f71ca..1cd4bbb8f 100644
--- a/hexrd/ui/calibration/auto/powder_runner.py
+++ b/hexrd/ui/calibration/auto/powder_runner.py
@@ -66,7 +66,7 @@ def _run(self):
             fwhm_estimate = options['initial_fwhm']
 
         # Get an intensity-corrected masked dict of the images
-        img_dict = HexrdConfig().masked_images_dict
+        img_dict = HexrdConfig().create_masked_images_dict()
 
         statuses = self.refinement_flags_without_overlays
         self.cf = statuses
diff --git a/hexrd/ui/calibration/calibration_runner.py b/hexrd/ui/calibration/calibration_runner.py
index ac02a985e..f44219cb1 100644
--- a/hexrd/ui/calibration/calibration_runner.py
+++ b/hexrd/ui/calibration/calibration_runner.py
@@ -388,7 +388,7 @@ def run_calibration(self):
         flags = HexrdConfig().get_statuses_instrument_format()
         instr.calibration_flags = flags
 
-        img_dict = HexrdConfig().masked_images_dict
+        img_dict = HexrdConfig().create_masked_images_dict()
 
         instr_calibrator = run_calibration(picks, instr, img_dict, materials)
         self.write_instrument_to_hexrd_config(instr)
@@ -753,7 +753,7 @@ def auto_pick_powder_points(self):
         options = HexrdConfig().config['calibration']['powder']
         self.instr = create_hedm_instrument()
 
-        img_dict = HexrdConfig().masked_images_dict
+        img_dict = HexrdConfig().create_masked_images_dict()
 
         statuses = HexrdConfig().get_statuses_instrument_format()
         self.instr.calibration_flags = statuses
@@ -835,7 +835,7 @@ def auto_pick_laue_spots(self):
         self.async_runner.run(self.run_auto_laue_pick)
 
     def run_auto_laue_pick(self):
-        img_dict = HexrdConfig().masked_images_dict
+        img_dict = HexrdConfig().create_masked_images_dict()
 
         # These are the options the user chose earlier...
         options = HexrdConfig().config['calibration']['laue_auto_picker']
diff --git a/hexrd/ui/calibration/stereo_plot.py b/hexrd/ui/calibration/stereo_plot.py
index e6b938e44..66bdbd462 100644
--- a/hexrd/ui/calibration/stereo_plot.py
+++ b/hexrd/ui/calibration/stereo_plot.py
@@ -42,7 +42,7 @@ def extent(self):
 
     @property
     def raw_img_dict(self):
-        return HexrdConfig().masked_images_dict
+        return HexrdConfig().create_masked_images_dict()
 
     @property
     def stereo_size(self):
diff --git a/hexrd/ui/hexrd_config.py b/hexrd/ui/hexrd_config.py
index 3943ca804..4ede9f72e 100644
--- a/hexrd/ui/hexrd_config.py
+++ b/hexrd/ui/hexrd_config.py
@@ -890,14 +890,21 @@ def raw_masks_dict(self):
 
         return masks_dict
 
-    @property
-    def masked_images_dict(self):
+    def create_masked_images_dict(self, fill_value=0):
         """Get an images dict where masks have been applied"""
         images_dict = self.images_dict
+        have_masks = len(self.visible_masks)
         for det, mask in self.raw_masks_dict.items():
             for name, img in images_dict.items():
+                if (have_masks and
+                        np.issubdtype(type(fill_value), np.floating) and
+                        not np.issubdtype(img.dtype, np.floating)):
+                    img = img.astype(float)
                 if det == name:
-                    img[~mask] = 0
+                    # Masks always exist but may not be masking any regions out.
+                    # Only use the fill value if any of the masks are
+                    # actually being applied (visible masks).
+                    img[~mask] = fill_value if have_masks else 0
 
         return images_dict
 
diff --git a/hexrd/ui/image_canvas.py b/hexrd/ui/image_canvas.py
index 406921107..a65e308f0 100644
--- a/hexrd/ui/image_canvas.py
+++ b/hexrd/ui/image_canvas.py
@@ -199,7 +199,7 @@ def load_images(self, image_names):
     def unscaled_image_dict(self):
         # Returns a dict of the unscaled images
         if self.mode == ViewType.raw:
-            return HexrdConfig().masked_images_dict
+            return HexrdConfig().create_masked_images_dict(fill_value=np.nan)
         else:
             # Masks are already applied...
             return {'img': self.iviewer.img}