put down in black and white
put something down in black and whiteand set something down in black and white
Fig. to write down the terms of an agreement; to draw up a written contract; to put the details of something down on paper. (Alludes to black ink and white paper.) We agree on all the major points. Now, let's set it down in black and white. I think I understand what you are talking about, but we need to put down the details in black and white.