Index: trunk/ppMerge/src/ppMergeCombine.c
===================================================================
--- trunk/ppMerge/src/ppMergeCombine.c	(revision 7260)
+++ trunk/ppMerge/src/ppMergeCombine.c	(revision 7355)
@@ -85,4 +85,5 @@
                     // Only reading and writing the first readout in each cell (plane 0)
                     if (pmReadoutReadNext(stack->data[k], fits, 0, options->rows)) {
+                        pmReadoutSetMask(stack->data[k]);
                         numRead++;
                     }