diff --git a/rtengine/imagesource.h b/rtengine/imagesource.h
index 52949756c..958956c60 100644
--- a/rtengine/imagesource.h
+++ b/rtengine/imagesource.h
@@ -109,7 +109,7 @@ public:
     virtual ImageData*     getImageData () = 0;
     virtual ImageMatrices* getImageMatrices () = 0;
     virtual bool        isRAW() const = 0;
-    virtual DCPProfile* getDCP(ColorManagementParams cmp, ColorTemp &wb)
+    virtual DCPProfile* getDCP(const ColorManagementParams &cmp, ColorTemp &wb)
     {
         return NULL;
     };