diff --git a/setup.cfg b/setup.cfg
index 837b79f..7744687 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,6 +1,6 @@
 [metadata]
 name = pyspectacle
-version = 3.1.0
+version = 3.1.1
 author = Olivier Burggraaff
 author_email = burggraaff@strw.leidenuniv.nl
 description = SPECTACLE camera calibration module
diff --git a/spectacle/io.py b/spectacle/io.py
index 05c099f..2bf0340 100644
--- a/spectacle/io.py
+++ b/spectacle/io.py
@@ -2,6 +2,7 @@
 import exifread
 import numpy as np
 import os
+from string import ascii_letters
 from pathlib import Path
 from matplotlib import pyplot as plt
 from .camera import load_camera, find_root_folder, load_json, write_json
@@ -196,7 +197,7 @@ def split_exposure_time(path):
     For a filename `x.z`, the returned value is `float(x)`.
     For a filename `x_y.z`, the returned value is `float(x/y)`.
     """
-    without_letters = path.stem.strip("t_jmeansd")  # strip underscores, leading t, trailing "mean"/"stds"
+    without_letters = path.stem.strip(ascii_letters+"_")  # strip underscores, leading t, trailing "mean"/"stds"
     if "_" in without_letters:
         numerator, denominator = without_letters.split("_")
         time = float(numerator)/float(denominator)