Index: trunk/psModules/src/imcombine/pmSubtractionSimple.c
===================================================================
--- trunk/psModules/src/imcombine/pmSubtractionSimple.c	(revision 35775)
+++ trunk/psModules/src/imcombine/pmSubtractionSimple.c	(revision 35784)
@@ -182,5 +182,6 @@
   }
   
-
+  bool oldThreads = psImageConvolveSetThreads(true); // Old value of threading in psImageConvolve
+  
   int maskBox = (int) ceil(sigmaKern * 1.1774); // diameter is 1/2 FWHM
   int maskBlank = 8;  // I should be able to get this from a reference, right?
@@ -387,4 +388,6 @@
   psFree(outHeader);
 
+  psImageConvolveSetThreads(oldThreads);
+  
   //
   // Return