diff --git a/whitematteranalysis/congeal_multisubject.py b/whitematteranalysis/congeal_multisubject.py
index c12e5bf..0c107cd 100644
--- a/whitematteranalysis/congeal_multisubject.py
+++ b/whitematteranalysis/congeal_multisubject.py
@@ -193,9 +193,9 @@ def iterate(self):
             
         # make a directory for the current iteration
         if self.mode == "Nonrigid":
-            dirname = f"iteration_{self.total_iterations:05d}_sigma_{self.sigma:03d}_grid_{self.nonrigid_grid_resolution:03d}"
+            dirname = f"iteration_{self.total_iterations:05d}_sigma_{int(self.sigma):03d}_grid_{int(self.nonrigid_grid_resolution):03d}"
         else:
-            dirname = f"iteration_{self.total_iterations:05d}_sigma_{self.sigma:03d}"
+            dirname = f"iteration_{self.total_iterations:05d}_sigma_{int(self.sigma):03d}"
 
         outdir = os.path.join(self.output_directory, dirname)
         if not os.path.exists(outdir):
@@ -346,9 +346,9 @@ def iterate(self):
         if have_mpl:
             plt.figure(0)
             if self.mode == "Nonrigid":
-                fname_fig_base = f"iteration_{self.total_iterations:05d}_sigma_{self.sigma:03d}_grid_{self.nonrigid_grid_resolution:03d}"
+                fname_fig_base = f"iteration_{self.total_iterations:05d}_sigma_{int(self.sigma):03d}_grid_{int(self.nonrigid_grid_resolution):03d}"
             else:
-                fname_fig_base = f"iteration_{self.total_iterations:05d}_sigma_{self.sigma:03d}_"
+                fname_fig_base = f"iteration_{self.total_iterations:05d}_sigma_{int(self.sigma):03d}_"
             # Place the legend below the plot so it does not overlap it when there are many subjects
             #lgd = plt.legend(loc='upper center', bbox_to_anchor=(0.5, -0.15), fancybox=False, shadow=False, ncol=1)
             fname_fig = f'objectives_per_subject_{fname_fig_base}.pdf'
@@ -405,9 +405,9 @@ def save_transformed_polydatas(self, intermediate_save=False, midsag_symmetric=F
             # Make a directory for the current iteration.
             # This directory name must match the one created above in the iteration.
             if self.mode == "Nonrigid":
-                dirname = f"iteration_{self.total_iterations:05d}_sigma_{self.sigma:03d}_grid_{self.nonrigid_grid_resolution:03d}"
+                dirname = f"iteration_{self.total_iterations:05d}_sigma_{int(self.sigma):03d}_grid_{int(self.nonrigid_grid_resolution):03d}"
             else:
-                dirname = f"iteration_{self.total_iterations:05d}_sigma_{self.sigma:03d}"
+                dirname = f"iteration_{self.total_iterations:05d}_sigma_{int(self.sigma):03d}"
             outdir = os.path.join(self.output_directory, dirname)
             if not os.path.exists(outdir):
                 os.makedirs(outdir)
diff --git a/whitematteranalysis/congeal_to_atlas.py b/whitematteranalysis/congeal_to_atlas.py
index ba02f08..9b1b47f 100644
--- a/whitematteranalysis/congeal_to_atlas.py
+++ b/whitematteranalysis/congeal_to_atlas.py
@@ -108,7 +108,7 @@ def iterate(self):
         self.total_iterations += 1
 
         # make a directory for the current iteration
-        dirname = f"iteration_{self.total_iterations:05d}_sigma_{ self.sigma:05d}"
+        dirname = f"iteration_{self.total_iterations:05d}_sigma_{int(self.sigma):05d}"
         outdir = os.path.join(self.output_directory, dirname)
         if not os.path.exists(outdir):
             os.makedirs(outdir)
@@ -163,7 +163,7 @@ def save_transformed_polydata(self, intermediate_save=False):
 
         if intermediate_save:
             # make a directory for the current iteration
-            dirname = f"iteration_{self.total_iterations:05d}_sigma_{self.sigma:05d}"
+            dirname = f"iteration_{self.total_iterations:05d}_sigma_{int(self.sigma):05d}"
             outdir = os.path.join(self.output_directory, dirname)
             if not os.path.exists(outdir):
                 os.makedirs(outdir)