diff --git a/openflexure_microscope/utilities.py b/openflexure_microscope/utilities.py
index 3a52ece9..ba926b34 100644
--- a/openflexure_microscope/utilities.py
+++ b/openflexure_microscope/utilities.py
@@ -1,5 +1,6 @@
 import copy
 import operator
+from fractions import Fraction
 from functools import reduce
 from contextlib import contextmanager
 
@@ -56,4 +57,4 @@ def entry_by_id(id: str, object_list: list):
     for o in object_list:
         if o.id == id:
             found = o
-    return found
\ No newline at end of file
+    return found