diff --git a/src/calibre/ebooks/__init__.py b/src/calibre/ebooks/__init__.py
index a1026e97d6..084b91430f 100644
--- a/src/calibre/ebooks/__init__.py
+++ b/src/calibre/ebooks/__init__.py
@@ -240,7 +240,7 @@ def generate_masthead(title, output_path=None, width=600, height=60):
         font = ImageFont.truetype(font_path, 48)
     except:
         font = ImageFont.truetype(default_font, 48)
-    text = title.encode('utf-8')
+    text = title.encode('utf-8') if isinstance(title, unicode) else title
     width, height = draw.textsize(text, font=font)
     left = max(int((width - width)/2.), 0)
     top = max(int((height - height)/2.), 0)