diff --git a/PIL/ImageMorph.py b/PIL/ImageMorph.py
index 7996a48aa..ca9b3bb80 100644
--- a/PIL/ImageMorph.py
+++ b/PIL/ImageMorph.py
@@ -195,7 +195,7 @@ class MorphOp:
             raise Exception('No operator loaded')
         
         outimage = Image.new(image.mode, image.size, None)
-        count = _imagingmorph.apply(self.lut, image.im.id, outimage.im.id)
+        count = _imagingmorph.apply(bytes(self.lut), image.im.id, outimage.im.id)
         return count, outimage
     
     def match(self, image):
@@ -205,7 +205,7 @@ class MorphOp:
         if self.lut is None:
             raise Exception('No operator loaded')
         
-        return  _imagingmorph.match(self.lut, image.im.id)
+        return  _imagingmorph.match(bytes(self.lut), image.im.id)
 
     def get_on_pixels(self, image):
         """Get a list of all turned on pixels in a binary image
diff --git a/_imagingmorph.c b/_imagingmorph.c
index 68a1db35b..7e7fdd879 100644
--- a/_imagingmorph.c
+++ b/_imagingmorph.c
@@ -45,19 +45,19 @@ apply(PyObject *self, PyObject* args)
         return NULL;
     }
 
-    if (!PyByteArray_Check(py_lut)) {
-        PyErr_SetString(PyExc_RuntimeError, "The morphology LUT is not a byte array");
+    if (!PyBytes_Check(py_lut)) {
+        PyErr_SetString(PyExc_RuntimeError, "The morphology LUT is not a bytes object");
         return NULL;
     }
 
-    lut_len = PyByteArray_Size(py_lut);
+    lut_len = PyBytes_Size(py_lut);
 
     if (lut_len < LUT_SIZE) {
         PyErr_SetString(PyExc_RuntimeError, "The morphology LUT has the wrong size");
         return NULL;
     }
 
-    lut = PyByteArray_AsString(py_lut);
+    lut = PyBytes_AsString(py_lut);
 
     imgin = (Imaging) i0;
     imgout = (Imaging) i1;
@@ -152,19 +152,19 @@ match(PyObject *self, PyObject* args)
         return NULL;
     }
 
-    if (!PyByteArray_Check(py_lut)) {
-        PyErr_SetString(PyExc_RuntimeError, "The morphology LUT is not a byte array");
+    if (!PyBytes_Check(py_lut)) {
+        PyErr_SetString(PyExc_RuntimeError, "The morphology LUT is not a bytes object");
         return NULL;
     }
 
-    lut_len = PyByteArray_Size(py_lut);
+    lut_len = PyBytes_Size(py_lut);
 
     if (lut_len < LUT_SIZE) {
         PyErr_SetString(PyExc_RuntimeError, "The morphology LUT has the wrong size");
         return NULL;
     }
 
-    lut = PyByteArray_AsString(py_lut);
+    lut = PyBytes_AsString(py_lut);
     imgin = (Imaging) i0;
 
     if (imgin->type != IMAGING_TYPE_UINT8 &&