diff --git a/src/calibre/ebooks/html.py b/src/calibre/ebooks/html.py
index 2883e39f8a..0b4f69b38b 100644
--- a/src/calibre/ebooks/html.py
+++ b/src/calibre/ebooks/html.py
@@ -859,7 +859,7 @@ class Processor(Parser):
             except ValueError:
                 setting = ''
             face = font.attrib.pop('face', None)
-            if face is not None:
+            if face:
                 faces = []
                 for face in face.split(','):
                     face = face.strip()