Index: trunk/psModules/src/detrend/pmDark.h
===================================================================
--- trunk/psModules/src/detrend/pmDark.h	(revision 16841)
+++ trunk/psModules/src/detrend/pmDark.h	(revision 16949)
@@ -7,4 +7,6 @@
 
 #define PM_DARK_ANALYSIS_ORDINATES "DARK.ORDINATES" // Name for dark ordinates in the cell analysis metadata
+#define PM_DARK_ANALYSIS_NORM "DARK.NORM" // Name for dark normalisation concept in cell analysis metadata
+#define PM_DARK_HEADER_NORM "PSDRKNRM"  // Header keyword for dark normalisation concept
 
 // An ordinate for fitting darks
@@ -26,4 +28,5 @@
                    const psArray *inputs, // Input readouts for combination
                    psArray *ordinates,  // Ordinates for fitting
+                   const char *normConcept, // Concept name to use to divide input pixel values
                    int iter,            // Number of rejection iterations
                    float rej,           // Rejection threshold (standard deviations)
@@ -82,10 +85,12 @@
 // Write dark table to FITS file
 bool pmDarkWrite(psFits *fits,          // FITS file to which to write
-                 const psMetadata *header, // Header to write
-                 const psArray *ordinates // Dark ordinates to write
+                 psMetadata *header,    // Header to write
+                 const psArray *ordinates, // Dark ordinates to write
+                 const char *normConcept // Normalisation concept name
     );
 
 // Read dark table from FITS file
-psArray *pmDarkRead(psFits *fits        // FITS file to read
+psArray *pmDarkRead(psString *normConcept, // Normalisation concept name
+                    psFits *fits        // FITS file to read
     );