Bleed, margins and safe zones for a first print file
Three terms, three rectangles. Get them right and your first file will come back from the printer as you drew it.
6min read · Printing
The first time you send a file to a print shop, a few terms come up that nobody explained: trim, bleed, safe zone. They describe three nested rectangles on every page, and they exist because cutting paper is not perfectly precise.
Trim: the finished page
The trim size is the page as the reader sees it. A5 is 148 x 210 mm. After printing, the paper is cut to this size, so the trim line is where the blade is aimed. Real blades drift a little. A cut can land a millimetre or so to either side of the intended line, and that is normal.
Bleed: the extra you do not see
If your design has a colour or a picture that reaches the edge, the cut must not reveal white paper. The solution is bleed: extend the colour or image beyond the trim line by a few millimetres, so a cut that wanders slightly still lands inside coloured area.
The common default is 3 mm. For an A5 page that means a file of 154 x 216 mm, which is 148 + 3 + 3 by 210 + 3 + 3. Some printers ask for 5 mm, and large-format or newspaper work may differ, so check your printer’s specification. The Folding Table’s print-file tab gives the figure for your chosen size at 3 mm.
Everything the page needs to look right at the edge, whether a background colour, a photograph or a border, must run to the bleed edge. Text, logos and faces must not.
Safe zone: where to keep important things
The safe zone is the inverse of bleed. It is the area inside the trim where nothing important should sit too close to the edge. The common figure is 5 mm inside the trim, sometimes written as a margin. Anything inside the safe zone survives a cut that drifts a millimetre or two.
The rule of thumb for a booklet is to keep text well inside it. A margin of 10 mm or more looks better and gives room for creep on thicker booklets. On the spine side, leave extra, because pages curve into the fold and the last few millimetres are hard to read.
Putting it on a page
In a layout program, set up your document at the trim size, add the bleed in the document settings, and draw guides for the safe zone. Place background elements so they extend to the bleed edge. Place text inside the guides.
When you export, choose the option to include bleed. If your program supports crop marks, switch them on only if the printer asks for them. Some printers prefer a clean file without marks, because they apply their own.
Covers and the spine
A saddle-stitched booklet has no spine you can print on, so a cover design is two pages: front and back. A perfect-bound book has a spine whose width depends on the page count and paper. For that, your printer will give you a template, and it overrides the generic advice here.
Sheet size and the flat size
The printer prints on a sheet larger than your page, then cuts. The print-file tab gives a flat sheet size for the layout you chose. If your pages are A5 and you fold A4 sheets, the flat size is A4 and bleed is handled by the print shop’s own trimming margin. If you plan to print pages on A3 and cut, bleed matters at every cut. Ask whether the shop wants pages individually or imposed, and what bleed it expects.
Colour and resolution, briefly
For photographs, 300 pixels per inch at the printed size is the common target. That is 1748 x 2480 pixels for an A5 page without bleed, as an approximation. Convert text to outlines or embed the fonts when exporting. If your printer uses CMYK, ask whether they convert for you, because colours can shift.
A checklist
- Page set at the trim size, plus bleed.
- Backgrounds and pictures extended into the bleed.
- Text and faces inside the safe zone.
- Extra space on the spine side.
- Fonts embedded or converted.
- A PDF exported with bleed, in reading order unless the printer asks otherwise.
When the printer says something different
Print shops have their own machines and cutters, and their numbers can differ from these defaults. When they differ, follow the shop. The numbers here are the common starting point so you can make a sensible first file and understand the conversation when you ask. A single email with the page size, count, paper and binding, which the table can write for you, usually gets a precise answer within a day.