What is Bleed?
A bleed is simply extra background image that goes beyond the cut edge of the product, this allows your images or colors to be edge to edge rather than have a white border. On a press or copy machine, the artwork must be printed on a larger sheet of paper and then trimmed down to size. If you do not allow for a 1/8 (.125) of an inch bleed, any misalignment can result in cutting variances and the artwork not running to the edge of the paper.
If you have designed a standard 3.5" x 2" business card with a photograph covering the whole area, you will need to enlarge that photograph to 3.75" x 2.25". This will make the photograph extend 1/8" on every side of the page. The same will apply to a brochure cut to 8.5" x 11" adding the 1/8" bleed area resulting in a 8.75" x 11.25" document, some programs have built in bleed page settings but many like Photoshop do not in this case simply make your document the size of the bleed and create a margin guide that will bring you in by 1/4" this will move your layout back from the cut edge and into the safezone so that nothing gets cut off during cutting.
Why is adding a Bleed necessary?
While our machines do a good job of keeping the alignment of each printed page, each sheet of paper can be a small difference in size or travel through the machine in a different way. Small mechanical variations can also end up leaving a hairline white edge where there should be no white edge at all, if the image is not extended beyond the final trim size. Extending images 1/8" beyond the final trim size guarantees that images truly will go all the way to the edge of the printed paper.