A new feature in PDF 1.3 was the ability to define a
document that has information beyond its final trim size. In the
graphic industry, this information usually includes bleed, registration
marks and other print and color control strips. Using the View
Page Boxestool 
, you
can easily preview the information outside of the final trim size
of your document.
This information is defined in the application that was used to create the original PDF file, for example, Adobe InDesign or Quark XPress. Once they are made visible using PitStop Pro, these elements can be edited, added, or removed, just like any other graphic object.
Some PDF documents are generated without any bleed, registration marks
or other print and color strips. When you click the View Page
Boxes button for
these documents, the page will appear the same (except for a thin
trim line drawn at the edges of the image).