diff --git a/skimage/util/dtype.py b/skimage/util/dtype.py
index ca8568b3784..1c594534b5f 100644
--- a/skimage/util/dtype.py
+++ b/skimage/util/dtype.py
@@ -13,6 +13,8 @@
                np.int16: (-32768, 32767),
                np.int64: (-2**63, 2**63 - 1),
                np.uint64: (0, 2**64 - 1),
+               np.int32: (-2**31, 2**31 - 1),
+               np.uint32: (0, 2**32 - 1),
                np.float32: (-1, 1),
                np.float64: (-1, 1)}