Index: trunk/ippconfig/recipes/ppStack.config
===================================================================
--- trunk/ippconfig/recipes/ppStack.config	(revision 42558)
+++ trunk/ippconfig/recipes/ppStack.config	(revision 42844)
@@ -239,4 +239,25 @@
 END
 
+XCSTACK_UNIONS_DR4 METADATA
+  CONVOLVE          BOOL  FALSE           # Convolve images when stacking?
+  MATCH.ZERO.POINTS BOOL  TRUE            # Convolve images when stacking?
+  
+  COMBINE.ITER    F32     0.0             # Number of rejection iterations per input
+  COMBINE.REJ     F32    10.0             # Rejection threshold in combination (sigma)
+  COMBINE.SYS     F32     0.1             # Relative systematic error in combination
+  COMBINE.DISCARD F32     0.0             # Discard fraction for Olympic weighted mean
+  
+  COMBINE.PERCENT         BOOL  TRUE      # Use a single percentile clipping?
+  COMBINE.REJECT.FRACTION F32   0.0       # fraction of outliers to reject in percentile clipping
+  
+  SKIP.MISSING.INPUTS BOOL FALSE          # If some input warp images are missing, make the stack anyway
+  
+  SKIP.BG.SUB         BOOL TRUE            # Bypass background subtraction?
+
+  OUTPUT.NOCOMP       BOOL FALSE # use filerules that make compressed outputs
+  OUTPUT.LOGFLUX      BOOL TRUE  # choose a log-scaling for output images
+  OUTPUT.DEEPEXP      BOOL TRUE  # allow exptime maps with dynamic range up to 2^16 (64k) seconds
+END
+
 TEST1 METADATA
   CONVOLVE          BOOL  FALSE           # Convolve images when stacking?