diff --git a/rtengine/rawimage.cc b/rtengine/rawimage.cc
index 3f4b2ac3f..919b1c7be 100644
--- a/rtengine/rawimage.cc
+++ b/rtengine/rawimage.cc
@@ -580,7 +580,9 @@ int RawImage::loadRaw (bool loadData, bool closeFile, ProgressListener *plistene
         if (cc) {
             for (int i = 0; i < 4; i++) {
                 if (RT_blacklevel_from_constant) {
-                    black_c4[i] = cblack[i] + cc->get_BlackLevel(i, iso_speed);
+                    int blackFromCc = cc->get_BlackLevel(i, iso_speed);
+                    // if black level from camconst > 0xffff it is an absolute value.
+                    black_c4[i] = blackFromCc > 0xffff ? (blackFromCc & 0xffff) : blackFromCc + cblack[i];
                 }
 
                 // load 4 channel white level here, will be used if available