diff --git a/ietf/utils/pdf.py b/ietf/utils/pdf.py
index c4d39601c..989e1a871 100644
--- a/ietf/utils/pdf.py
+++ b/ietf/utils/pdf.py
@@ -10,11 +10,11 @@ import re
 def pdf_pages(filename):
     """Return number of pages in PDF."""
     try:
-        infile = io.open(filename, "r")
+        infile = io.open(filename, "rb")
     except IOError:
         return 0
     for line in infile:
-        m = re.match(r'\] /Count ([0-9]+)',line)
+        m = re.match(br'\] /Count ([0-9]+)',line)
         if m:
             return int(m.group(1))
     return 0