diff --git a/docs/Changelog.rst b/docs/Changelog.rst
index c4bb1ea5..dc4ff076 100644
--- a/docs/Changelog.rst
+++ b/docs/Changelog.rst
@@ -3,9 +3,14 @@ Change Log
 ==========
 
 
+Version 0.6.3
+=============
+Return UserWarning for compositions outside of the calibration ranges for the epsilon absorption coefficients in function calculate_concentrations and calculate_epsilon, UserWarning for when data do not span the full wavenumber range of 1000-5500 cm^-1 whilst using class SampleDataLoader. Thanks to Dr. Shuo Ding and Emilia Pelegano-Titmuss for identifying common errors during test usage, which contributed to these improvements.
+
+
 Version 0.6.2
 =============
-Return ValueError for mismatched samples in peak height and composition DataFrames, UserWarning for missing data columns in composition DataFrame.
+Return ValueError for mismatched samples in peak height and composition DataFrames in function calculate_concentrations, UserWarning for missing data columns in composition DataFrame in class SampleDataLoader. Thanks to Dr. Shuo Ding for identifying common errors during test usage, which contributed to these improvements.
 
 
 Version 0.6.1
diff --git a/src/PyIRoGlass/_version.py b/src/PyIRoGlass/_version.py
index a0c2f6a2..82af2612 100644
--- a/src/PyIRoGlass/_version.py
+++ b/src/PyIRoGlass/_version.py
@@ -5,4 +5,4 @@
 # 1) we don't load dependencies by storing it in __init__.py
 # 2) we can import it in setup.py for the same reason
 # 3) we can import it into your module
-__version__ = "0.6.2"
+__version__ = "0.6.3"
diff --git a/src/PyIRoGlass/core.py b/src/PyIRoGlass/core.py
index 4d5e3fd3..59b03db9 100644
--- a/src/PyIRoGlass/core.py
+++ b/src/PyIRoGlass/core.py
@@ -97,6 +97,13 @@ def load_spectrum_directory(self, wn_high=5500, wn_low=1000):
                 df = df.iloc[::-1]
             df.set_index("Wavenumber", inplace=True)
             spectrum = df.loc[wn_low:wn_high]
+            if wn_low == 1000 and wn_high == 5500:
+                if not (spectrum.index.min() <= wn_low and 
+                        spectrum.index.max() >= wn_high):
+                    warnings.warn(f"{file} data do not span the required "
+                                  f"wavenumbers of 1000-5500 cm^-1.",
+                                  UserWarning,
+                                  stacklevel=2)
             dfs.append(spectrum)
             files.append(file)
 
@@ -692,6 +699,7 @@ def calculate_baselines(dfs_dict, export_path):
     indparams = [wavenumber, PCmatrix, H2Om1635_PCmatrix, Nvectors]
 
     full_path = os.path.join(os.getcwd(), "FINALDATA")
+    file_name = "DF.csv" if export_path is None else f"{export_path}_DF.csv"
 
     # Create DataFrames to store peak height data:
     # P_ = peak_, _BP = best parameter, #_STD = _stdev
@@ -1354,6 +1362,15 @@ def calculate_epsilon(composition, T, P):
     covz_error_SiAl = np.zeros((2, 2))
     covz_error_NaCa = np.zeros((2, 2))
 
+    # Define calibration ranges
+    tau_ranges = {
+        "epsilon_H2Om_5200": (0.6, 0.8641748075261225),
+        "epsilon_OH_4500": (0.6, 0.8641748075261225),
+        "epsilon_H2Ot_3550": (0.5078379123837519, 0.9023427189457927),
+        "epsilon_H2Om_1635": (0.627337511542476, 0.86)
+    }
+    eta_range = (0.23157895182099122, 0.8406489374848108)
+
     # Loop through and calculate for all MI or glass compositions.
     for i in composition.index:
         # Calculate extinction coefficients with best-fit parameters
@@ -1412,6 +1429,40 @@ def calculate_epsilon(composition, T, P):
             }
         )
 
+        # Check whether Tau and Eta are in calibration ranges, warn if not
+        # Same ranges for epsilon_H2Om_5200 and epsilon_OH_4500, simplify
+        if not (tau_ranges["epsilon_H2Om_5200"][0] 
+                <= SiAl_tot[i] <= tau_ranges["epsilon_H2Om_5200"][1]):
+            warnings.warn(f"Tau ({round(SiAl_tot[i], 4)}) for {i} "
+                        f"is outside the calibration range for "
+                        f"epsilon_H2Om_5200 and epsilon_OH_4500. "
+                        f"Use caution.", 
+                        UserWarning,
+                        stacklevel=2)
+
+        if not (tau_ranges["epsilon_H2Ot_3550"][0] 
+                <= SiAl_tot[i] <= tau_ranges["epsilon_H2Ot_3550"][1]):
+            warnings.warn(f"Tau ({round(SiAl_tot[i], 4)}) for {i} "
+                        f"is outside the calibration range for "
+                        f"epsilon_H2Ot_3550. Use caution.",
+                        UserWarning,
+                        stacklevel=2)
+
+        if not (tau_ranges["epsilon_H2Om_1635"][0] 
+                <= SiAl_tot[i] <= tau_ranges["epsilon_H2Om_1635"][1]):
+            warnings.warn(f"Tau ({round(SiAl_tot[i], 4)}) for {i} "
+                        f"is outside the calibration range for "
+                        f"epsilon_H2Om_1635. Use caution.",
+                        UserWarning,
+                        stacklevel=2)
+
+        if not (eta_range[0] <= Na_NaCa[i] <= eta_range[1]):
+            warnings.warn(f"Eta ({round(Na_NaCa[i], 4)}) for {i} "
+                        f"is outside the calibration range for "
+                        f"epsilon_CO2. Use caution.",
+                        UserWarning,
+                        stacklevel=2)
+
     return epsilon