diff --git a/base.py b/base.py
index 227c90d..f3dffb9 100644
--- a/base.py
+++ b/base.py
@@ -112,7 +112,7 @@ class BaseWindow(QMainWindow):
             print("date_str", date_str, flush=True)
 
             def extract_and_attach(i, nfig, name, all_fig_data):
-                canvas = 'Canvas {1}'.format(i+1)
+                canvas = 'Canvas {0}'.format(i+1)
                 name_base = name.replace(' ', '_').lower()
 
                 if all_fig_data[canvas] is not None: