In contrast to the above, I would not go anywhere near DDX if shot at 400. DDX gives very full speed (which for this film is about 1000/1250) so if you know you have exposed at 400, its best to use something that sheds speed, not provides it. D76 or ID11 straight is another option, but few developers will drop speed as well as undiluted Perceptol or Microdol. Just my 2 cents... but DDX will give a solid stop more speed than undiluted perceptol...