diff --git a/src/calibre/gui2/preferences/coloring.py b/src/calibre/gui2/preferences/coloring.py
index 162070d051..ae0c7ff315 100644
--- a/src/calibre/gui2/preferences/coloring.py
+++ b/src/calibre/gui2/preferences/coloring.py
@@ -61,7 +61,9 @@ class ConditionEditor(QWidget):  # {{{
             'int' : (
                 (_('is equal to'), 'eq'),
                 (_('is less than'), 'lt'),
-                (_('is greater than'), 'gt')
+                (_('is greater than'), 'gt'),
+                (_('is set'), 'is set'),
+                (_('is not set'), 'is not set')
             ),
             'datetime' : (
                 (_('is equal to'), 'eq'),
diff --git a/src/calibre/library/coloring.py b/src/calibre/library/coloring.py
index e877db474b..e2a24eb739 100644
--- a/src/calibre/library/coloring.py
+++ b/src/calibre/library/coloring.py
@@ -129,6 +129,10 @@ class Rule(object):  # {{{
         return "check_yes_no('%s', %s)"%(col, test)
 
     def number_condition(self, col, action, val):
+        if action == 'is set':
+            return "test(field('%s'), '1', '')"%col
+        if action == 'is not set':
+            return "test(field('%s'), '', '1')"%col
         lt, eq, gt = {
                 'eq': ('', '1', ''),
                 'lt': ('1', '', ''),