Index: trunk/ppSub/src/ppSubReadout.c
===================================================================
--- trunk/ppSub/src/ppSubReadout.c	(revision 14482)
+++ trunk/ppSub/src/ppSubReadout.c	(revision 14495)
@@ -362,4 +362,12 @@
     }
 
+    // Add additional data to the header
+    pmFPAfile *refFile = psMetadataLookupPtr(NULL, config->files, "PPSUB.REF"); // Reference file
+    pmFPAfile *inFile = psMetadataLookupPtr(NULL, config->files, "PPSUB.INPUT"); // Input file
+    psMetadataAddStr(outHDU->header, PS_LIST_TAIL, "PPSUB.REFERENCE", 0,
+                     "Subtraction reference", refFile->filename);
+    psMetadataAddStr(outHDU->header, PS_LIST_TAIL, "PPSUB.INPUT", 0,
+                     "Subtraction input", inFile->filename);
+
     memCheck("header");