When an image runs off the edge of a page, printers call that a “bleed”. It’s a commonly used technique, and can really add a professional feel to your publication.
It’s important to realize a few things if you want image to bleed off the edge of your sheet.
First, this is something that is generally done on printing presses. If you’re planning on outputting on a laser or inkjet printer, the machine needs somewhere to grab the paper as it pulls it through the machine; image will not go there and you’ll be left with a white space on the edge of your sheet. You could trim the white area off, but because most of these machines print standard paper sizes (8 1/2 x 11 or 11 x 17), you’d be left with something undersized by the time it was trimmed. As well, because there are no devices to make sure the image goes in exactly the same place from sheet to sheet (what printers call in register), you may get inconsistent trim results.
Conventional print presses get around this by printing larger sheets and trimming inside the image area. Except for small duplicators, they tend to handle sheets at least 9 x 12 inches, and more typically 19 x 23. This allows a printer to print multiple pages on a single press sheet (for more on this, click here), and trim them down after they’re printed.
Printing presses generally have a registration device that gives each sheet of paper a little nudge before it enters the press where the ink gets applied. This ensures each sheet is identically positioned before it gets ink put down, giving more consistent trim results.
Another considerations: The amount of image you need to run off the edge of the sheet matters. Printers like to see 1/4 inch of excess image to trim off; this way there’s no chance of seeing blank paper on the edge of your sheet.
Remember to centre your subject where it will be after the area is trimmed, not before; otherwise you may find part of your subject being trimmed off.
Bleed can really enhance the appearance of your project, but it’s important to do it right.