Print production: bleed, resolution and getting it right first time

Printers reject files constantly, almost always for the same handful of reasons. Understanding them will save you days of back and forth even if you never open a design application.

Bleed, trim and safe area

Printing happens on oversized sheets that are then cut down, and cutting has a tolerance of a millimetre or two. Bleed is artwork extended beyond the final size — usually 3mm or 0.125in — so a slight cutting error shows more artwork rather than a white sliver. The safe area is the inset margin where important content should stay, for the same reason in the other direction.

A design with a coloured background and no bleed will come back with white edges on some copies. This is the most common print error there is.

Resolution

• Standard print: 300 dpi at final size. A 100mm wide image needs roughly 1200 pixels.
• Large format viewed at distance: 100 to 150 dpi at final size is usually fine, and full resolution would produce an unmanageable file.
• Vector artwork has no resolution and scales infinitely. Logos and type should always be vector.
• Upscaling does not add detail. A 72 dpi web image cannot be made print-ready by changing the number in a dialogue box.

Colour mode

Convert to CMYK before sending, or agree with the printer that they will convert. Letting the RIP convert unexpectedly is how bright colours turn muddy without warning. For rich blacks in large areas, use a build rather than 100% K alone — most printers specify their preferred mix, so ask.

Use spot colours only where you have agreed to pay for them. A stray spot colour in a file quoted as four-colour causes either a rejection or a surprise invoice.

Fonts and transparency

• Convert type to outlines, or embed the fonts. Otherwise your typeface may be silently substituted.
• Flatten transparency if the printer asks for it. Some older workflows handle it unpredictably.
• Keep a live editable version for yourself before outlining. Outlined type cannot be edited.

What to send

1. 1A print-ready PDF, generated with the printer's preset if they supply one.
2. 2Bleed included and crop marks on.
3. 3CMYK, with spot colours only where intended.
4. 4Fonts outlined or embedded.
5. 5Images at correct resolution and linked or embedded properly.
6. 6A clearly named file. "final_final_v3_USE_THIS.pdf" causes genuine errors in production.

Ask for a proof

For anything above a small run, ask for a proof and check it properly: text accuracy, colour, position, and crucially the trim. A digital proof catches content errors; a printed proof on the actual stock catches colour and finish surprises. The cost of a proof is trivial against a reprint.