diff --git a/src/darsia/restoration/averaging.py b/src/darsia/restoration/averaging.py
index ea288d5f..33dee971 100644
--- a/src/darsia/restoration/averaging.py
+++ b/src/darsia/restoration/averaging.py
@@ -62,7 +62,8 @@ def __init__(
 
         # User output
         logger.info(
-            f"Number of zero indices in pore volume identification: {len(self.zero_indices[0])}"
+            f"""Number of zero indices in pore volume identification: """
+            f"""{len(self.zero_indices[0])}"""
         )
 
     @overload  # type: ignore [override]