Bleeds is a term used in printing for images or graphics that extend beyond the edge of the paper that gets trimmed off. Printing presses, like conventional laser and ink jet style printers, cannot print all the way to the edge of a sheet of paper. Many printed works, however, appear to be printed all the way to the edge of the paper. This is accomplished by printing the material on a larger sheet of paper beyond the desired final size of the printout. After this, all excess printed material is cut off. When the final work is viewed by anyone, the “finished work” gives the illusion that the printing press had actually printed your design all the way to the edge of the paper. This small excess amount of artwork on each edge of the paper is called “bleed.”
Basically a bleed is the extension of the image past the edge of the paper. If you are designing a piece that has an image or shape that goes all the way to the edge of the paper, then you need to add a bleed. When printing in a press, a project is often printed on a larger sheet of paper and then cut down to final size. If there were no bleed then when cut down you would have some pages that had a slight white border because they moved in the cutter a millimeter or so. With a bleed it is impossible to get a white border because your image overlaps the cut line.
The amount of bleed needed depends on a number of things including; page size, project type and type of printing. Usually 1/8" (.125) is good for most things but for large projects you may need more. A printer can usually reduce the amount of bleed but cannot extend it. About 90% of the work that goes on a typical press however is printed on oversized sheets. Paper is ordered by a printer in sizes like 23x35, 19x25, 25x38, and 26x40 among others. When cut down to run size they end up like 8.75x11.5, which is cut down to 8.5x11 after printing. So if your job is 8.5x11 or 11x17 then there should be very little if any extra cost.
Essentially, bleed is the term for printing that goes right to the edge of the paper. The way to do this is to make your document around quarter of an inch too big in both dimensions. For instance, if the final size is 8.5’ x 11”, make your document 8.75” x11.25”. Now, draw guides on the layout around .25” from the edge. Create your design with the idea that the layout will be cut off where those guides are. Make sure that any photographs or backgrounds that you want to bleed go clear out to the perimeter of the document, past the guidelines. After the printing is done, the printer will trim off that extra .25” all the way around. That’s all that’s to it!