diff --git a/geomagio/imagcdf/ImagCDFFactory.py b/geomagio/imagcdf/ImagCDFFactory.py
index 72a0dc19b945c05201b9bce93c107897c6c68411..414aaf99417421080a09fe368d7ea022b0b34b93 100644
--- a/geomagio/imagcdf/ImagCDFFactory.py
+++ b/geomagio/imagcdf/ImagCDFFactory.py
@@ -131,6 +131,8 @@ class ImagCDFFactory(TimeseriesFactory):
             temperature_index = 0
             for trace in timeseries:
                 channel = trace.stats.channel
+                if channels and channel not in channels:
+                    continue
                 var_name = f"GeomagneticField{channel}"
                 # if channel in REAL_TEMPERATURE:
                 #     temperature_index += 1  # MUST INCREMENT INDEX BEFORE USING