diff --git a/app/pdb/drawable-color-cmds.c b/app/pdb/drawable-color-cmds.c
index c986ce11dd..1790293999 100644
--- a/app/pdb/drawable-color-cmds.c
+++ b/app/pdb/drawable-color-cmds.c
@@ -740,7 +740,7 @@ register_drawable_color_procs (GimpPDB *pdb)
                                "gimp-drawable-brightness-contrast");
   gimp_procedure_set_static_help (procedure,
                                   "Modify brightness/contrast in the specified drawable.",
-                                  "This procedures allows the brightness and contrast of the specified drawable to be modified. Both 'brightness' and 'contrast' parameters are defined between -0.5 and 0.5.",
+                                  "This procedures allows the brightness and contrast of the specified drawable to be modified. Both 'brightness' and 'contrast' parameters are defined between -1.0 and 1.0.",
                                   NULL);
   gimp_procedure_set_static_attribution (procedure,
                                          "Spencer Kimball & Peter Mattis",
@@ -756,13 +756,13 @@ register_drawable_color_procs (GimpPDB *pdb)
                                g_param_spec_double ("brightness",
                                                     "brightness",
                                                     "Brightness adjustment",
-                                                    -0.5, 0.5, -0.5,
+                                                    -1.0, 1.0, -1.0,
                                                     GIMP_PARAM_READWRITE));
   gimp_procedure_add_argument (procedure,
                                g_param_spec_double ("contrast",
                                                     "contrast",
                                                     "Contrast adjustment",
-                                                    -0.5, 0.5, -0.5,
+                                                    -1.0, 1.0, -1.0,
                                                     GIMP_PARAM_READWRITE));
   gimp_pdb_register_procedure (pdb, procedure);
   g_object_unref (procedure);
diff --git a/libgimp/gimpdrawablecolor_pdb.c b/libgimp/gimpdrawablecolor_pdb.c
index 92d5c50b27..67e2932c85 100644
--- a/libgimp/gimpdrawablecolor_pdb.c
+++ b/libgimp/gimpdrawablecolor_pdb.c
@@ -47,7 +47,7 @@
  *
  * This procedures allows the brightness and contrast of the specified
  * drawable to be modified. Both 'brightness' and 'contrast' parameters
- * are defined between -0.5 and 0.5.
+ * are defined between -1.0 and 1.0.
  *
  * Returns: TRUE on success.
  *
diff --git a/pdb/groups/drawable_color.pdb b/pdb/groups/drawable_color.pdb
index fba4c569d9..1f0628d8f8 100644
--- a/pdb/groups/drawable_color.pdb
+++ b/pdb/groups/drawable_color.pdb
@@ -22,7 +22,7 @@ sub drawable_brightness_contrast {
     $help = <<'HELP';
 This procedures allows the brightness and contrast of the specified drawable to
 be modified.  Both 'brightness' and 'contrast' parameters are defined between
--0.5 and 0.5.
+-1.0 and 1.0.
 HELP
 
     &std_pdb_misc;
@@ -32,9 +32,9 @@ HELP
     @inargs = (
 	{ name => 'drawable', type => 'drawable',
 	  desc => 'The drawable' },
-	{ name => 'brightness', type => '-0.5 <= float <= 0.5',
+	{ name => 'brightness', type => '-1.0 <= float <= 1.0',
 	  desc => 'Brightness adjustment' },
-	{ name => 'contrast', type => '-0.5 <= float <= 0.5',
+	{ name => 'contrast', type => '-1.0 <= float <= 1.0',
 	  desc => 'Contrast adjustment' }
     );