Quote Originally Posted by scootermm
Yeah using a normal #2 pencil. I use a sheet of the paper that goes between each piece of sheet film in the film boxes. Its a good easy way to mark up the area to be coated. just four small marks in the corners suffices just fine usually.

hope that helps
What he said. Just enough of a mark to be able to re-position the negative when the coating is dry, and to see where to coat when applying the emulsion. With most processes, the finished exposed print has dark enough borders that you can't see the pencil marks anymore.