diff --git a/src/spexipy/spexical.py b/src/spexipy/spexical.py
index 00e7086..4afae17 100644
--- a/src/spexipy/spexical.py
+++ b/src/spexipy/spexical.py
@@ -66,7 +66,10 @@ class SpeXICAL:
             self.fine_gain = self._load_frame(np.float32)
             self.fine_offset = self._load_frame(np.float32)
 
-        self.pixel_mask = self._load_frame(np.uint16)
+        if self.format_version < 3:
+            self.pixel_mask = self._load_frame(np.uint8)
+        else:
+            self.pixel_mask = self._load_frame(np.uint16)
 
         self.comment = self._file.read(self.file_size - self._min_size)