Among one of the most misunderstood document setup requirements is bleed and live area. In the realm of commercial printing this is critically important and differs from printing on your home printer, which usually (but not always) can get away with a simple 8.5″ x 11″ word document.
Bleed is the extra area around the document that is meant to be cut off. The technical reason is that most large types of cutters, that are cutting the document after it was printed on a larger-sized sheet, need a bit of “wiggle room” to safely cut. Without that wiggle room, there’s a risk of a white space in between the cut and the image that should be to the edge.
Typically ArborOakland recommends adding an 1/8″ bleed (.125″) to all documents. Large format items like banners require around 2″ of bleed to play it safe.
Sometimes it isn’t possible to get that bleed that is needed, due to time constraints or the client might not have the ability or the files necessary to add bleed. In that case the best bet is usually to undercut the file to ensure that there is no white areas around. This means that the document is slightly undersized as a sacrifice to ensure that it looks good.
The best bet is to design a document with bleed in mind by creating the file with bleeds to start. Adding an 1/8″ bleed can solve a lot of issues before they crop up. Also remember when exporting the file as a PDF that the bleeds are carried over to the print file.