diff --git a/src/damaris/experiments/Experiment.py b/src/damaris/experiments/Experiment.py
index 70a25d8..0393b32 100644
--- a/src/damaris/experiments/Experiment.py
+++ b/src/damaris/experiments/Experiment.py
@@ -13,7 +13,7 @@ class StateSimple(StateBase):
         super(StateSimple, self).__init__()
         if time < 0:
             raise AssertionError("time for state is negative!")
-        self.time = time
+        self.time = float(time)
         self.content = content
 
     def to_xml(self, indent = ""):
@@ -190,7 +190,7 @@ class Experiment:
 
         Typically only used in very special cases.
         """
-        self.state_list.append('<state time="%s">\n' % repr(time))
+        self.state_list.append('<state time="%s">\n' % repr(float(time)))
         self.total_time[-1] += time
 
     ## End of *state_start*
@@ -679,19 +679,19 @@ class Experiment:
                     value=""
                 elif type(value) is float or isinstance(value, numpy.floating):
                     type_string="Float"
-                    value=repr(value)
+                    value=repr(float(value))
                 elif type(value) is int or isinstance(value, numpy.integer):
                     type_string="Int"
-                    value=repr(value)
+                    value=repr(int(value))
                 elif type(value) is int:
                     type_string="Long"
                     value=repr(value)
                 elif type(value) is complex or isinstance(value, numpy.complexfloating):
                     type_string="Complex"
-                    value=repr(value)
+                    value=repr(complex(value))
                 elif type(value) is bool or isinstance(value, numpy.bool_):
                     type_string="Boolean"
-                    value=repr(value)
+                    value=repr(bool(value))
                 elif type(value) in (str,):
                     type_string="String"
                 else:
diff --git a/tests/test_Experiment.py b/tests/test_Experiment.py
index 6479b63..6e063c9 100644
--- a/tests/test_Experiment.py
+++ b/tests/test_Experiment.py
@@ -42,6 +42,34 @@ class TestExperimentPhase(unittest.TestCase):
         e.rf_pulse(length=1e-6, phase=-90, source=0)
         self.assertEqual(phase_of_state(e.state_list.list[0]), 270.0)
 
+    def test_numpy_scalars_in_description(self):
+        """Test that description items with numpy scalars (e.g. from lin_range)
+        are written as plain numbers so the result script can parse them again."""
+        import numpy as np
+        from damaris.tools.ranges import lin_range
+        e = Experiment()
+        e.set_description("tau", lin_range(1e-6, 3e-6, 1e-6)[0])
+        e.set_description("n", np.int64(42))
+        xml = e.write_xml_string()
+        items = {key: (typ, text)
+                 for key, typ, text in
+                 re.findall(r'<item key="([^"]+)" type="([^"]+)">([^<]*)</item>', xml)}
+        self.assertEqual(items["tau"][0], "Float")
+        self.assertEqual(items["n"][0], "Int")
+        self.assertEqual(float(items["tau"][1]), 1e-6)
+        self.assertEqual(int(items["n"][1]), 42)
+
+    def test_numpy_scalar_state_times(self):
+        """Test that numpy scalar times do not end up as np.float64(...) in the XML."""
+        import numpy as np
+        e = Experiment()
+        e.wait(np.float64(1e-6))
+        e.state_start(np.float64(2e-6))
+        xml = e.write_xml_string()
+        self.assertNotIn("np.float64", xml)
+        self.assertIn('<state time="1e-06"/>', xml)
+        self.assertIn('<state time="2e-06">', xml)
+
 
 if __name__ == "__main__":
     unittest.main()