Index: trunk/ppImage/src/ppImageArguments.c
===================================================================
--- trunk/ppImage/src/ppImageArguments.c	(revision 14000)
+++ trunk/ppImage/src/ppImageArguments.c	(revision 16844)
@@ -10,4 +10,5 @@
     fprintf(stderr, "\t-stats STATS.mdc: Output statistics into STATS.mdc\n");
     fprintf(stderr, "\t-isfringe: The input image contains fringe data.\n");
+    fprintf(stderr, "\t-isdark: The input image contains dark data.\n");
     fprintf(stderr, "\t-usemask MASKVAL: Use this mask value (override recipe).\n");
     fprintf(stderr, "\t-chip CHIPNUM: Only process this chip number.\n");
@@ -71,4 +72,9 @@
                           "Input is fringe image", true);
     }
+    if ((argnum = psArgumentGet(argc, argv, "-isdark"))) {
+        psArgumentRemove(argnum, &argc, argv);
+        psMetadataAddBool(config->arguments, PS_LIST_TAIL, "INPUT_IS_DARK", PS_META_REPLACE,
+                          "Input is dark image", true);
+    }
 
     // the following options override the PPIMAGE recipe options