diff --git a/rtengine/rawimage.cc b/rtengine/rawimage.cc
index 8d7292113..ebfe45f44 100644
--- a/rtengine/rawimage.cc
+++ b/rtengine/rawimage.cc
@@ -333,6 +333,11 @@ skip_block:
     }
 
     if (colors == 1)
+        // there are monochrome cameras with wrong matrix. We just replace with this one.
+        rgb_cam[0][0] = 1; rgb_cam[1][0] = 0; rgb_cam[2][0] = 0;
+        rgb_cam[0][1] = 0; rgb_cam[1][1] = 1; rgb_cam[2][1] = 0;
+        rgb_cam[0][2] = 0; rgb_cam[1][2] = 0; rgb_cam[2][2] = 1;
+
         for (c = 1; c < 4; c++) {
             cblack_[c] = cblack_[0];
         }
diff --git a/rtengine/rawimagesource.cc b/rtengine/rawimagesource.cc
index 8be6cfb1d..d6ae6a199 100644
--- a/rtengine/rawimagesource.cc
+++ b/rtengine/rawimagesource.cc
@@ -1593,7 +1593,7 @@ int RawImageSource::load (const Glib::ustring &fname)
 
     for (int i = 0; i < 3; i++)
         for (int j = 0; j < 3; j++) {
-            imatrices.rgb_cam[i][j] = ri->get_rgb_cam(i, j);
+            imatrices.rgb_cam[i][j] = ri->get_colors() == 1 ? (i == j) : ri->get_rgb_cam(i, j);
         }
 
     // compute inverse of the color transformation matrix