diff --git a/screening/source/java/ch/systemsx/cisd/openbis/dss/etl/dynamix/HCSImageFileExtractor.java b/screening/source/java/ch/systemsx/cisd/openbis/dss/etl/dynamix/HCSImageFileExtractor.java
index a3538845d5b1078edecc5185811192c0e39ff0d4..76f3e513e42864ed0e50de57a8d9505e5455939f 100644
--- a/screening/source/java/ch/systemsx/cisd/openbis/dss/etl/dynamix/HCSImageFileExtractor.java
+++ b/screening/source/java/ch/systemsx/cisd/openbis/dss/etl/dynamix/HCSImageFileExtractor.java
@@ -132,8 +132,9 @@ public class HCSImageFileExtractor extends AbstractHCSImageFileExtractor
     private WellLocation getWellLocation(File imageFile, final String[] tokens)
     {
         Map<DynamixWellPosition, WellLocation> map = getWellLocationMapping(imageFile);
+        String posToken = tokens[2].substring("pos".length());
         DynamixWellPosition wellPos =
-                WellLocationMappingUtils.parseWellPosition(tokens[0], tokens[2]);
+                WellLocationMappingUtils.parseWellPosition(tokens[0], posToken);
         return map.get(wellPos);
     }
 
diff --git a/screening/source/java/ch/systemsx/cisd/openbis/dss/etl/dynamix/WellLocationMappingUtils.java b/screening/source/java/ch/systemsx/cisd/openbis/dss/etl/dynamix/WellLocationMappingUtils.java
index 68d8100e1a49fda865de4d87cbb100c14822e7ad..4cc53b7f978fe81a99684680c4fa540ca3a25436 100644
--- a/screening/source/java/ch/systemsx/cisd/openbis/dss/etl/dynamix/WellLocationMappingUtils.java
+++ b/screening/source/java/ch/systemsx/cisd/openbis/dss/etl/dynamix/WellLocationMappingUtils.java
@@ -43,8 +43,7 @@ class WellLocationMappingUtils
 
     public static DynamixWellPosition parseWellPosition(String sideToken, String posToken)
     {
-        String posNumber = posToken.substring("pos".length());
-        return new DynamixWellPosition(new Integer(posNumber), isRight(sideToken));
+        return new DynamixWellPosition(new Integer(posToken), isRight(sideToken));
     }
 
     private static Map<DynamixWellPosition, WellLocation> createMapping(