diff --git a/tests/visual_tests/test.py b/tests/visual_tests/test.py
index 52f2e9a7b..28fdb19c2 100755
--- a/tests/visual_tests/test.py
+++ b/tests/visual_tests/test.py
@@ -129,8 +129,9 @@ def render(filename, width, height, bbox, quiet=False):
                 pass # will have been generated by agg test
             else:
                 # cairo and agg differ in alpha for reasons unknown, so don't test it for now
-                diff = compare(actual_cairo, expected, threshold=1, alpha=False)
-                report(diff,quiet,threshold=1)
+                diff_threshold = 4
+                diff = compare(actual_cairo, expected, threshold=diff_threshold, alpha=False)
+                report(diff,quiet,threshold=diff_threshold)
         except Exception, e:
             sys.stderr.write(e.message + '\n')
             fail(actual_cairo,expected,str(e.message))