diff --git a/src/ndv/controllers/_array_viewer.py b/src/ndv/controllers/_array_viewer.py
index d47139f6..cdc1a559 100644
--- a/src/ndv/controllers/_array_viewer.py
+++ b/src/ndv/controllers/_array_viewer.py
@@ -335,7 +335,7 @@ def _update_visible_sliders(self) -> None:
             return
         hidden_indices: set[int] = set(self._data_model.normed_visible_axes)
         if self._data_model.display.channel_mode.is_multichannel():
-            if ch := self._data_model.normed_channel_axis:
+            if (ch := self._data_model.normed_channel_axis) is not None:
                 hidden_indices.add(ch)
 
         # hide singleton axes
diff --git a/src/ndv/models/_data_display_model.py b/src/ndv/models/_data_display_model.py
index 810812d8..45b5bf5e 100644
--- a/src/ndv/models/_data_display_model.py
+++ b/src/ndv/models/_data_display_model.py
@@ -200,7 +200,7 @@ def current_slice_requests(self) -> list[DataRequest]:
 
         # if we need to request multiple channels (composite mode or RGB),
         # ensure that the channel axis is also sliced
-        if c_ax := self.normed_channel_axis:
+        if (c_ax := self.normed_channel_axis) is not None:
             if self.display.channel_mode.is_multichannel():
                 if not isinstance(requested_slice.get(c_ax), slice):
                     requested_slice[c_ax] = slice(None)