Ink Doesn't Undo: A Screen Designer's Field Guide to Sending Files to a UK Printer

There is a particular kind of email that arrives on a Friday afternoon. It is from a printer, it has a PDF attached, and the subject line says something like 'Query — bleed on back cover'. You open it, see a white sliver where your deep blue background should be, and realise you have exported the screen version and hoped for the best. The printer, as ever, found it.

Print files are not screen files with a different extension. They are a separate deliverable, with their own rules, their own review step and their own handover note. Treat them that way and the Friday email becomes a boring confirmation instead of a small emergency.

The print file is a second deliverable

When you quote a job, the design is one thing; the print-ready artwork is another. Not a bigger thing, just a different one. A screen layout can be 1440 pixels wide and full of RGB shadows; a print file needs a physical size, a colour space, a bleed, and a clear instruction about what happens at the edge. If you would not send a client a homepage with no mobile layout, do not send a printer a file with no bleed.

Name it like a deliverable too. Something like ClientName_Poster_A2_v3_PRINT.pdf tells everyone this is not the file for the website. Keep the working file and the print file in the same job folder but in separate subfolders. Future you will be grateful.

Before the export dialogue: a five-minute audit

Start with the boring numbers. Final trim size in millimetres, not pixels. Bleed at 3mm on every edge unless the printer has asked for something else. A safe area inside the trim so no text sits close enough to be clipped by a guillotine that has had a long day. Images at 300ppi at the size they will actually print, not the size they were when you dragged them in.

Check colour mode. CMYK for process jobs, spot colours named correctly if the job uses them, and no stray RGB swatches hiding in a gradient or a drop shadow. Fonts either embedded or outlined — but if you outline, keep an editable version because the client will ask for a text change after proof. And check that your document has an output intent set, not just a CMYK mode. A PDF with no output intent is a printer guessing.

Export settings that travel well

For most UK commercial printers in 2026, PDF/X-4 is the sensible default. It handles transparency and layers without flattening everything into a mystery, and it carries the output intent. PDF/X-1a is still useful for older workflows or a printer who asks for it specifically. Either way, tick the boxes for crop marks and bleed, and make sure the bleed value in the export matches the bleed in the document.

Do not add registration marks unless the printer wants them. Crop marks, yes. A colour bar, sometimes. A giant 'FINAL' stamp across the artwork, no. The goal is a file the prepress operator can open without having to guess what you meant.

The black point and the overprint trap

Small black text should normally be 100% K, not a rich black made of all four inks. Rich black is for large solids where you want depth; on 9pt body copy it can cause registration fringing if the press drifts. Check your black swatches before you export, not after.

Overprint is the other quiet one. Black text set to overprint can disappear against a dark background, or look muddy on a busy image. Open the PDF in Acrobat, use Output Preview, and look at the separations. If you do not know what you are looking at, ask the printer for a preflight report. Most will run one and tell you what they see. That is not a failure; it is a conversation.

Ask about paper before you design the finish

Paper stock changes colour. A warm grey on uncoated stock will look different from the same grey on silk. If the job is colour-critical, ask the printer which stock and which profile they recommend before you finalise the palette. A soft proof on a calibrated monitor is useful; a hard proof on the actual stock is evidence. Do not promise a client an exact match on an uncoated paper without saying what that means.

The proof is a decision, not a formality

When the proof arrives, read it like a contract. Check trim, folds, image crops, contact details, spellings, and the back page. Sign it off in writing, with the date and the file version. If the client wants to approve it, make sure they know what they are approving. A proof approval is the point where 'I thought it would be more blue' stops being a design conversation and becomes a reprint conversation.

The handshake email

Keep it short and specific. Something like: 'Attached is the print-ready PDF for [job], version [x], sized [trim] with [3mm] bleed. Stock: [stock]. Finish: [finish]. Quantity: [number]. Proof: [hard/soft/none]. Deadline: [date]. Please confirm receipt and flag any preflight issues before [date].' That email does more work than a dozen apologetic follow-ups. It also gives the printer a single place to reply, which means fewer phone calls and fewer surprises.

A checklist you can paste into the job folder

• Trim size confirmed in millimetres; bleed 3mm on all edges.
• Images 300ppi at final size; no stretched logos.
• CMYK or spot colours checked; no RGB stragglers.
• Black text is 100K; rich black only where intended.
• Overprint checked in Output Preview.
• Fonts embedded or outlined; editable copy kept.
• PDF/X-4 exported with crop marks and bleed.
• Paper stock and finish confirmed with the printer.
• Proof approved in writing by the right person.
• Handshake email sent with file name, version and deadline.

The printer will always find the thing you missed. The trick is to find it first, in your own studio, while there is still time to fix it calmly.