diff --git a/coders/dpx.c b/coders/dpx.c
index 0dd07c9..3309fee 100644
--- a/coders/dpx.c
+++ b/coders/dpx.c
@@ -1112,7 +1112,7 @@
     if (count != (ssize_t) extent)
       status=MagickFalse;
     q=QueueAuthenticPixels(image,0,offset,image->columns,1,exception);
-    if (q == (const Quantum *) NULL)
+    if (q == (Quantum *) NULL)
       {
         status=MagickFalse;
         continue;