diff --git a/MagickWand/mogrify.c b/MagickWand/mogrify.c
index a70f5bb..4acb036 100644
--- a/MagickWand/mogrify.c
+++ b/MagickWand/mogrify.c
@@ -1077,7 +1077,7 @@
             {
               q=GetCacheViewAuthenticPixels(mask_view,0,y,mask_image->columns,1,
                 exception);
-              if (q == (const Quantum *) NULL)
+              if (q == (Quantum *) NULL)
                 break;
               for (x=0; x < (ssize_t) mask_image->columns; x++)
               {