diff --git a/src/PIL/TiffImagePlugin.py b/src/PIL/TiffImagePlugin.py
index 73e9a2763..7d4d8c2a9 100644
--- a/src/PIL/TiffImagePlugin.py
+++ b/src/PIL/TiffImagePlugin.py
@@ -993,7 +993,7 @@ class TiffImageFile(ImageFile.ImageFile):
 
         logger.debug("*** TiffImageFile._open ***")
         logger.debug("- __first: {}".format(self.__first))
-        logger.debug("- ifh: {}".format(ifh))
+        logger.debug("- ifh: {!r}".format(ifh))  # Use !r to avoid str(bytes)
 
         # and load the first frame
         self._seek(0)