Bleed refers to a background color, graphic, or image that extends to the edge of the finished paper size and beyond. It’s difficult for printing equipment to apply ink up to the cut edge of a sheet of paper. So an extra .125″ (3mm) margin is typically added on each side of the design, enabling the background color, graphic, or image to extend past (i.e., “bleed off”) the paper’s final trim edge. This extra bleed area will be cut off the printed sheet. For example, a letterhead sheet that incorporates bleed in its design will be 8.75″ x 11.25″ before being trimmed to a finished size of 8.5″ x 11″.
In contrast, a piece with no bleed keeps all the printed elements a minimum of .125″ (3mm) away from the edge of the paper on all four sides. Nothing is printed to the finished edge of the paper.