The live area is a guide to where the main body of the text, and pictures may be placed. Bleeds When an image is spread over the edge of a page, this is called a bleed, because ink from the printer bleeds off the edge of the paper. There is no damage to the printing press, because the pages are actually printed on paper that is larger than the finished, or trim, size. When the page has been printed it is cut down to the size required, and the image is cleanly cut at the page edge. The live area can also be divided into other sections - called columns.
Columns are vertical areas of a page that contain text or pictures.
An A4 page can be divided by any number of columns, although usually only as many as five. For pages with more than five columns, the text needs to be set at very small type sizes, otherwise only a few words can be printed in each column. Gutters Columns require white space between them so the structure of a page is easy to see. This space is called a gutter. If columns of text were placed on the page with no space between them, the page would be very grey and difficult to read.