Adobe Acrobat 7 Professional - Manual (Page 474)

Setting art, trim, and bleed box preferences
You can set the Page Display preferences to show any art, trim, and bleed boxes that are
defined in the Adobe PDF document.
To set the art, trim, and bleed box preferences:
1. Choose Edit > Preferences (Windows) or Acrobat > Preferences (Mac OS), and select
Page Display on the left side of the Preferences dialog box. (You can also choose
Preferences from the document pane menu.)
2. To display defined boxes in the PDF document, select Display Art, Trim, Bleed Boxes.