Print production: getting files ready for the printer

A design that looks perfect on screen can still fail at the printer. Text sits too close to the edge and gets cut, a photograph prints soft, or the organisation's blue comes back dull and purple. Most of these problems are decided before the file is sent, not on the press.

A UK reference guide on print-ready PDFs puts it simply: print-ready PDFs are PDFs created for the purpose of commercial printing.¹ There is also an international family of standards for this job. The PDF Association describes PDF/X as a strict subset of PDF designed for reliable print exchange, with rules on colours, fonts and content so that print files behave predictably.² You do not need to know the standard in detail, but you should know which version your printer wants.

Printers usually print on larger sheets and cut them down to the finished size. Crop marks show where to trim the design.³ Because the blade is never perfectly precise, anything designed to reach the edge of the page, such as a background colour or a full-page photograph, must extend beyond the trim line. This extra area is called bleed, and it ensures there are no unwanted white borders when the design is trimmed after printing.³

How much bleed? The UK guide says elements that go to the edge should extend beyond the crop marks by 3 mm minimum.¹ The US Department of Energy's print service asks for 1/8 inch of bleed beyond the trim marks on all four sides, which is almost the same.⁴ Always check your printer's own specification, especially for large-format banners, which often need more.

The opposite applies to text and logos. Keep them inside a safe margin, well away from the trim line, so that a small shift in cutting does not clip a word or a partner's logo. Canva's guidance notes that margins help a layout look balanced and ensure nothing is accidentally trimmed.³

Screens create colour from red, green and blue light (RGB). Full-colour documents are usually printed in four colour: cyan, magenta, yellow and black, known in the industry as CMYK.¹ The two systems cannot show exactly the same range of colours, so bright screen colours, such as vivid greens and electric blues, often print duller.

The Department of Energy's print service asks for all colours to be converted to CMYK and warns that RGB images may not convert as you would expect.⁴ Design tools reflect the same priority: Adobe Express preselects a CMYK colour profile when you download a print PDF, for colour accuracy in printing.⁵

In practice, use the CMYK values in your brand guidelines rather than letting software guess them from a web colour. If exact brand colour matters, for example on a large banner or a logo, ask the printer whether a spot colour or a printed test is worth it.

Images for print need far more pixels than images for the web. The Department of Energy's print service asks that all images, including charts and photographs, are a minimum of 300 dpi.⁴ That figure applies at the size the image will actually appear on the page: a photograph that is 300 dpi at postcard size will not be at A3.

Problems usually start with the source. Images saved from websites, social media or messaging apps are compressed and too small for print. In our own practice, we ask for the original camera file or the highest-resolution export, and we check effective resolution in the layout before export. Charts and logos are best kept as vector files, which stay sharp at any size.

If a font is missing on the printer's computer, the software will substitute another one and the layout will shift. The UK guide is clear that all the fonts used in a document need to be embedded within it.¹ The Department of Energy's print service also asks for all fonts, images and graphics to be embedded, and for the least amount of compression.⁴

Most printers will name a PDF/X preset. The two most common are PDF/X-1a and PDF/X-4. Under PDF/X-1a, print elements can only use CMYK, greyscale or spot colours, and no RGB is permitted.² PDF/X-4 allows transparency, which earlier versions forbade, and inherits the colour-managed rules of PDF/X-3.² If your printer does not say which they prefer, ask before you export.

Print-ready is not only a technical standard. A report or leaflet that people struggle to read has failed, however well it prints. Sensory Trust's clear print guidance recommends a minimum font size of 12 pt Arial, ideally 14 pt, and notes that the RNIB defines large print as 16 pt Arial or bigger.⁶

The same guidance advises maximising contrast between text and background, not overlaying text on images, and left-aligning text to avoid the uneven spaces of justified text.⁶ These choices cost nothing at the design stage and are expensive to fix after printing.

Always read a proof before approving a print run. A screen proof catches layout errors, but only a printed proof shows how colours, small text and photographs really look on paper. The Department of Energy's print service asks for a printed copy of the PDF, which it uses as a visual guide.⁴

Ask someone who did not design the file to read the proof. Check spelling, names, figures, logos, page order, contact details and partner logos against the approved text. Many printers will also check files for print suitability and advise of potential issues before production.¹ Treat that check as a safety net, not a substitute for your own sign-off.

Finally, send the printer a short written brief with the file: finished size, quantity, paper, finishing such as folding or binding, and the delivery date. Clear instructions avoid most of the questions that delay a job, and give everyone the same reference if something goes wrong.

• Document set to the finished page size
• Bleed of at least 3 mm, or the printer's specification
• Text and logos inside a safe margin
• Colours converted to CMYK using brand values
• Images at 300 dpi at their printed size
• Fonts embedded and the requested PDF/X preset used
• Clear print checked: size, contrast, no text over images
• Printed proof read and signed off by a second person