Index: /trunk/ippconfig/recipes/reductionClasses.mdc
===================================================================
--- /trunk/ippconfig/recipes/reductionClasses.mdc	(revision 42656)
+++ /trunk/ippconfig/recipes/reductionClasses.mdc	(revision 42657)
@@ -1,3 +1,14 @@
 # These reduction classes define recipes that go together as a group
+
+# the detrend reduction classes are used by the detrend ippScripts to select
+# the desired recipes for the different types of detrend products:
+
+## detrend_process_imfile.pl loads recipes (det_type)_PROCESS & (det_type)_JPEG_IMAGE
+## detrend_resid_imfile.pl loads either (det_type)_RESID OR (det_type)_VERIFY AND (det_type)_JPEG_RESID
+## detrend_stack.pl loads (det_type)_STACK
+
+# (det_type)_PROCESS & (det_type)_RESID are used to select PPIMAGE recipes
+# (det_type)_JPEG_IMAGE, (det_type)_JPEG_RESID are used to select JPEG recipes
+# (det_type)_STACK is used to select the PPMERGE recipe (NOTE: not ppStack)
 
 DETREND         METADATA