diff --git a/skimage/util/dtype.py b/skimage/util/dtype.py
index 3f85cc2b..e88545fc 100644
--- a/skimage/util/dtype.py
+++ b/skimage/util/dtype.py
@@ -304,7 +304,7 @@ def img_as_uint(image, force_copy=False):
 
     Notes
     -----
-    Negative input values will be shifted to the positive domain.
+    Negative input values will be clipped.
 
     """
     return convert(image, np.uint16, force_copy)
@@ -351,8 +351,7 @@ def img_as_ubyte(image, force_copy=False):
 
     Notes
     -----
-    If the input data-type is positive-only (e.g., uint16), then
-    the output image will still only have positive values.
+    Negative input values will be clipped.
 
     """
     return convert(image, np.uint8, force_copy)