diff --git a/adafruit_bitmap_font/bdf.py b/adafruit_bitmap_font/bdf.py
index 8dd919b..ec66d76 100644
--- a/adafruit_bitmap_font/bdf.py
+++ b/adafruit_bitmap_font/bdf.py
@@ -108,7 +108,7 @@ def _verify_bounding_box(self) -> None:
         try:
             self._boundingbox
         except AttributeError as error:
-            raise Exception(
+            raise RuntimeError(
                 "Source file does not have the FOUNTBOUNDINGBOX parameter"
             ) from error