diff --git a/lib/matplotlib/backends/backend_pdf.py b/lib/matplotlib/backends/backend_pdf.py
index a966cef7a981..5cb39490ffee 100644
--- a/lib/matplotlib/backends/backend_pdf.py
+++ b/lib/matplotlib/backends/backend_pdf.py
@@ -460,7 +460,10 @@ def __init__(self, filename):
         self.resourceObject = self.reserveObject('resources')
 
         root = {'Type': Name('Catalog'),
-                'Pages': self.pagesObject}
+                'Pages': self.pagesObject,
+                'Group': {'Type': Name('Group'),
+                          'S': Name('Transparency'),
+                          'CS': Name('DeviceRGB')}}
         self.writeObject(self.rootObject, root)
 
         revision = ''
@@ -519,9 +522,6 @@ def newPage(self, width, height):
                    'Resources': self.resourceObject,
                    'MediaBox': [0, 0, 72 * width, 72 * height],
                    'Contents': contentObject,
-                   'Group': {'Type': Name('Group'),
-                             'S': Name('Transparency'),
-                             'CS': Name('DeviceRGB')},
                    'Annots': self.pageAnnotations,
                    }
         pageObject = self.reserveObject('page')