diff --git a/Tests/test_color_lut.py b/Tests/test_color_lut.py
index 18b3f630f..3eb2bdcef 100644
--- a/Tests/test_color_lut.py
+++ b/Tests/test_color_lut.py
@@ -19,7 +19,6 @@ class TestColorLut3DCoreAPI(PillowTestCase):
                 b / float(size3D-1) if size3D != 1 else 0,
                 r / float(size1D-1) if size1D != 1 else 0,
                 g / float(size2D-1) if size2D != 1 else 0,
-                b / float(size3D-1) if size3D != 1 else 0,
             ][:channels]
             for b in range(size3D)
                 for g in range(size2D)
@@ -42,7 +41,7 @@ class TestColorLut3DCoreAPI(PillowTestCase):
 
         with self.assertRaisesRegexp(ValueError, "table_channels"):
             im.im.color_lut_3d('RGB', Image.LINEAR,
-                *self.generate_unit_table(6, 3))
+                *self.generate_unit_table(5, 3))
 
         with self.assertRaisesRegexp(ValueError, "table_channels"):
             im.im.color_lut_3d('RGB', Image.LINEAR,
@@ -60,6 +59,14 @@ class TestColorLut3DCoreAPI(PillowTestCase):
             im.im.color_lut_3d('RGB', Image.LINEAR,
                 *self.generate_unit_table(3, (66, 3, 3)))
 
+        with self.assertRaisesRegexp(ValueError, r"size1D \* size2D \* size3D"):
+            im.im.color_lut_3d('RGB', Image.LINEAR,
+                3, 2, 2, 2, [0, 0, 0] * 7)
+
+        with self.assertRaisesRegexp(ValueError, r"size1D \* size2D \* size3D"):
+            im.im.color_lut_3d('RGB', Image.LINEAR,
+                3, 2, 2, 2, [0, 0, 0] * 9)
+
     def test_correct_arguments(self):
         im = Image.new('RGB', (10, 10), 0)
 
@@ -124,6 +131,63 @@ class TestColorLut3DCoreAPI(PillowTestCase):
         im.im.color_lut_3d('RGBA', Image.LINEAR,
             *self.generate_unit_table(4, 3))
 
+    def test_units(self):
+        g = Image.linear_gradient('L')
+        im = Image.merge('RGB', [g, g.transpose(Image.ROTATE_90),
+                                 g.transpose(Image.ROTATE_180)])
+
+        # Fast test with small cubes
+        for size in [2, 3, 5, 7, 11, 16, 17]:
+            self.assert_image_equal(im, im._new(
+                im.im.color_lut_3d('RGB', Image.LINEAR,
+                    *self.generate_unit_table(3, size))))
+
+        # Not so fast
+        self.assert_image_equal(im, im._new(
+            im.im.color_lut_3d('RGB', Image.LINEAR,
+                *self.generate_unit_table(3, (2, 2, 65)))))
+
+    def test_channels_order(self):
+        g = Image.linear_gradient('L')
+        im = Image.merge('RGB', [g, g.transpose(Image.ROTATE_90),
+                                 g.transpose(Image.ROTATE_180)])
+
+        # Reverse channels by splitting and using table
+        self.assert_image_equal(
+            Image.merge('RGB', im.split()[::-1]),
+            im._new(im.im.color_lut_3d('RGB', Image.LINEAR,
+                3, 2, 2, 2, [
+                    0, 0, 0,  0, 0, 1,
+                    0, 1, 0,  0, 1, 1,
+
+                    1, 0, 0,  1, 0, 1,
+                    1, 1, 0,  1, 1, 1,
+                ])))
+
+    def test_overflow(self):
+        g = Image.linear_gradient('L')
+        im = Image.merge('RGB', [g, g.transpose(Image.ROTATE_90),
+                                 g.transpose(Image.ROTATE_180)])
+
+        transformed = im._new(im.im.color_lut_3d('RGB', Image.LINEAR,
+                3, 2, 2, 2,
+                [
+                    -1, -1, -1,   2, -1, -1,
+                    -1,  2, -1,   2,  2, -1,
+
+                    -1, -1,  2,   2, -1,  2,
+                    -1,  2,  2,   2,  2,  2,
+                ])).load()
+
+        self.assertEqual(transformed[0, 0], (0, 0, 255))
+        self.assertEqual(transformed[50, 50], (0, 0, 255))
+        self.assertEqual(transformed[255, 0], (0, 255, 255))
+        self.assertEqual(transformed[205, 50], (0, 255, 255))
+        self.assertEqual(transformed[0, 255], (255, 0, 0))
+        self.assertEqual(transformed[50, 205], (255, 0, 0))
+        self.assertEqual(transformed[255, 255], (255, 255, 0))
+        self.assertEqual(transformed[205, 205], (255, 255, 0))
+
 
 if __name__ == '__main__':
     unittest.main()
diff --git a/src/_imaging.c b/src/_imaging.c
index f023a6328..d1262f5b8 100644
--- a/src/_imaging.c
+++ b/src/_imaging.c
@@ -740,7 +740,6 @@ _prepare_lut_table(PyObject* table, Py_ssize_t table_size)
         } else {
             prepared[i] = table_data[i] * (255 << PRECISION_BITS) + 0.5;
         }
-        // printf("%f, %d ", table_data[i], prepared[i]);
     }
     
     #undef PRECISION_BITS