diff --git a/openflexure_microscope/utilities.py b/openflexure_microscope/utilities.py
index 1a36f86b..6f1deb16 100644
--- a/openflexure_microscope/utilities.py
+++ b/openflexure_microscope/utilities.py
@@ -59,7 +59,7 @@ def ndarray_to_json(arr: np.ndarray) -> JSONArrayType:
 
 
 def json_to_ndarray(json_dict: JSONArrayType):
-    if not json_dict.get("@type") != "ndarray":
+    if json_dict.get("@type") != "ndarray":
         logging.warning("No valid @type attribute found. Conversion may fail.")
     for required_param in ("dtype", "shape", "base64"):
         if not json_dict.get(required_param):