Four printed materials bleed refers to printing that goes past the edge of the paper so that when it’s trimmed the printing or color goes all the way to the edge of the paper.
To print a bleed a piece of paper larger than the document is used and then cut to the size required. If no bleed is used for the documents a thin white, possibly irregular, line may appear along the edges of the paper.
It is important to note, that no printing should go past the safety zone which is approximately 1/16″ inch.
Most bleed jobs require a 1/16″ bleed. If the job requires die cutting or is a booklet a 1/8″ bleed is required.