First used by Agha in the Vogue magazine in 1930, bleed refers to the printing of a design when the artwork extends beyond the final edge from at least an ⅛ inch to ¼” inch. It allows the image or elements on a page to go all the way to its edge without leaving a white border showing on the design.
How the bleed works when printing is that the safety margin left on the design is cut off. This extra edge is referred to as the trim edge.
The printer cannot just print a design all the way to the edge of the paper naturally because it would cause extra toner to drop inside the printer and create a huge mess. This is why the bleed system was set in place.
Instead, the design would be printed on an oversized sheet of paper and then trimmed down to the final size to avoid any printing imperfections such as hairline white margins.
The amount of bleed to leave on a file depends on what type of item is being created. An ⅛” inch is satisfactory on most pieces; however, larger items like outdoor banners can have a bleed up to 1 inch. The best way to handle this is to ask your print shop what they need.
Design programs like Adobe Illustrator and InDesign offer bleed setting options where the size of bleed can be inputted into the document and will even offer space markers to show the trim lines. Viewing the design in preview mode will show what the finished design will look like with the bleed cut off.
Common mistakes to avoid when wanting full bleed printing include adding a white border to be the “bleeds” of the design, potentially giving an unwanted tiny white border around the finished design.
Another mistake to avoid is putting important text or images too close to the design’s safety margin area where they could be cut off during the trimming process. Watch out for this, especially if a file’s dimensions need to be expanded for a document redesign to include bleed.