diff --git a/coders/dpx.c b/coders/dpx.c
index 4352435b4d..d1d329b1cf 100644
--- a/coders/dpx.c
+++ b/coders/dpx.c
@@ -1141,7 +1141,7 @@ static Image *ReadDPXImage(const ImageInfo *image_info,ExceptionInfo *exception)
       (void) CloseBlob(image);
       return(GetFirstImageInList(image));
     }
-  if (HeapOverflowSanityCheck(image->columns,4*image->depth) != MagickFalse)
+  if (HeapOverflowSanityCheck(image->columns,4*image->depth/8) != MagickFalse)
     ThrowReaderException(ResourceLimitError,"MemoryAllocationFailed");
   status=SetImageExtent(image,image->columns,image->rows,exception);
   if (status == MagickFalse)