Print shops don't print directly onto paper at the final size. Most jobs are printed on larger sheets that are then trimmed by machine. That cut is never perfectly exact; it can shift slightly. If a coloured background ends exactly at the edge, a thin white strip is left behind. In printing, that's known as a white sliver.
The solution is bleed. Everything that's meant to run to the edge, so backgrounds, images and areas of colour, is extended beyond the final size. Usually that's 3 mm on each side. The cut is then made inside this extra margin. Even if the cut shifts slightly, it still hits a printed area. Two more terms go with it:
- Crop marks are fine lines outside the bleed. They show the print shop where to cut.
- Safety margin: text, logos and important elements belong a little further in, away from the trim edge. How far is set out in the print shop's specifications.
For a business, this means: if the bleed is missing, the print shop will ask, or trim tight, and in the worst case the whole run ends up with white edges. That costs time and sometimes a second print run. On business cards, flyers and labels with a coloured background in particular, every white sliver stands out.
What to look out for: set up the document at the final size and define the bleed in the document settings, for example in InDesign or Affinity. Export a PDF in CMYK with bleed, crop marks and embedded fonts. Check your print shop's specifications, because some ask for more or less than 3 mm. When we prepare print files, we check the bleed before handing them over to the print shop.
An architecture practice in Zug orders business cards at 85 x 55 mm with a dark blue background. The print file therefore has to be 91 x 61 mm, which is 3 mm extra on each side. The blue runs right to the outer edge of this file. Name, phone number and logo sit with enough distance inside the 85 x 55 mm. After trimming, the blue runs cleanly to the edge. If the file had only measured 85 x 55 mm, some of the cards would show a thin white edge.