Printers print most pieces on a larger sheet and trim them to size afterwards. Trimming is never perfect, as a sheet can shift by a few tenths of a millimetre, so if the artwork stopped exactly at the cutting line, a thin white strip could be left at the edges.
It is worth setting up the bleed in the document at the start of the design, because otherwise every element reaching the edge of the page would have to be extended one by one later. In most design programs this is a separate setting that marks a thin frame around the artboard.
Bleed prevents this mistake. We extend the background colour and every element that reaches the edge of the page a few millimetres beyond the final size, so the print stays coloured right to the edge after trimming. The usual bleed is three millimetres, though the printer may ask for more, especially for packaging and large-format pieces.
Crop marks and the safe zone
Crop marks are short lines placed at the corners of the sheet that show the printer the limits of the final size. Most design programs place them automatically on export, though it is worth setting them as the printer asks.
The counterpart of the bleed is the safe zone on the inside edge of the page. No important text or logo may go here, because the machine could cut it off if the sheet shifts slightly. On a business card or a flyer this is a few millimetres, and on a box it has to be watched along the folds as well.
- Whether every element reaching the edge of the page bleeds to the specified size
- Whether the texts and logos sit inside the safe zone
- Whether the crop marks went into the file with the settings the printer asked for
- Whether the dieline lines are on a separate layer, so they do not print on the artwork
If you have not received specifications from the printer, ask for them, because the size of the bleed and the safe zone, and the form of the crop marks, can differ between printers.
These seem like small details, yet a missing bleed can mean that a whole print run has to be printed again. That is why during prepress we check every file for these points before it goes to the printer, so the printer accepts it in the first round.
