diff --git a/lib/interface/encode.c b/lib/interface/encode.c
index c2a8ac8..133ba60 100644
--- a/lib/interface/encode.c
+++ b/lib/interface/encode.c
@@ -133,6 +133,7 @@ extern int Encode(
         case 6:  // u4
             break;
         default:
+            printf("Unsupported dtype enum %d\n", type_enum);
             py_error("The input array has an unsupported dtype");
             return 5;
     }
diff --git a/openjpeg/utils.py b/openjpeg/utils.py
index 2ac4f1d..65fc592 100644
--- a/openjpeg/utils.py
+++ b/openjpeg/utils.py
@@ -66,8 +66,8 @@ class PhotometricInterpretation(IntEnum):
         "the input array has an unsupported number of columns, must be " "in (1, 65535)"
     ),
     5: (
-        "the input array has an unsupported dtype, only bool, u1, u2, i1 and "
-        "i2 are supported"
+        "the input array has an unsupported dtype, only bool, u1, u2, u4, i1, i2"
+        " and i4 are supported"
     ),
     6: "the input array must use little endian byte ordering",
     7: "the input array must be C-style, contiguous and aligned",