How to Prepare Print-Ready Files: A Prepress Checklist for Studios

What are the steps to prepare a print-ready file?

Prepress is everything between a finished design and a printing plate, cutter or output device. The printer will run its own checks, but it cannot know what you intended, so the studio checks first. Work through the same steps in the same order on every file. The order matters because later checks depend on earlier ones: there is no point checking overprint on a file that is the wrong size.

• 1. Get the printer's file specification: trim size, bleed, colour profile, black and overprint rules, export preset, dieline if any.
• 2. Set the document to the exact trim size, with bleed on every edge where artwork prints off the page.
• 3. Keep text and logos inside the safe area.
• 4. Check every image's effective resolution at its final printed size, and that no links are missing.
• 5. Set colour as the printer asks: process (CMYK), spot, or colour-managed. Make sure each brand colour is defined one way only.
• 6. Set small text and fine lines in 100% black; use the printer's rich black recipe only for large solid areas.
• 7. Check overprint with the overprint preview on, and remove any you did not set on purpose.
• 8. For packaging and die-cuts, place the current dieline on its own named, non-printing layer, with finishes on their own layers.
• 9. Compare the copy word for word with the last approved version.
• 10. Export with the printer's preset, run preflight, open the exported PDF and look at it at 100%.

What do bleed, trim and safe area mean?

Printers usually print several items on a larger sheet and cut a stack of sheets at once. The cut can drift slightly. Three zones absorb that drift. The trim is the finished size, where the blade is meant to cut. Bleed is extra artwork beyond the trim on any edge that prints to the edge, so a slightly off cut never shows a thin white line. The safe area is a margin inside the trim where text and logos stay, so a slightly off cut never clips them.

Bleed is commonly about 3 mm, or an eighth of an inch, and safe areas a few millimetres, but these are conventions, not rules. Large-format, packaging and some digital presses use different figures. Ask the printer and build to their numbers. Crop marks sit outside the bleed and must not touch the artwork.

Which colour mode should a print file use?

Colour depends on where the item will appear. RGB mixes light and is for screens. CMYK mixes four process inks and is for most print. A spot colour is a single pre-mixed ink, used when one colour has to match exactly every time, such as a logo colour on packaging. Define each brand colour once, in one table, in all of these forms, and copy from that table. The most common colour fault in practice is not choosing the wrong mode, it is defining the same colour two ways in one file, so the press prints two slightly different versions side by side.

What is the difference between rich black and 100% black, and what does overprint do?

100% black is one ink. Rich black adds some cyan, magenta or yellow beneath the black to make large areas look deeper. On a big solid panel that works well, if you use the printer's recipe and stay within its total ink limit. On small text it is a trap: four inks must land in exactly the same place on a moving press, and if they are slightly out of register every letter gets a coloured fringe. Set small text and fine lines in 100% black only.

Overprint tells the press to print one colour on top of another instead of knocking out the colour underneath. It is normal for black text on colour, and for some special layers such as white underprint or varnish. Set by accident on a white or light object, overprint can make that object disappear on press. Turn on overprint preview before you export, and look.

Which PDF should I send the printer?

Send the PDF the printer asks for, exported with their preset if they supply one. Many printers ask for a PDF/X file. The PDF Association describes PDF/X as a family of ISO standards for reliable print exchange. Two versions are common. PDF/X-1a allows only CMYK, greyscale and spot colour and does not allow live transparency, so transparency is flattened at export. PDF/X-4 allows transparency and colour-managed colour, which many modern workflows prefer.

Whatever the standard, embed or outline fonts as the printer asks, keep the preflight report with the job, and name the file so the version is obvious. Then open the exported PDF, not your working file, and check it. The export is what the printer receives.

How do I check packaging and label files?

Packaging adds two risks: shape and law. The shape comes from the dieline, the cutting and folding plan, which should come from the printer or converter for their machine and board. Confirm the revision in writing before final artwork. Put the dieline on its own named layer as a spot colour set not to print, keep glue areas clear where specified, and put foil, spot UV, emboss and white on separate named layers.

The law belongs to the client. Ingredients, allergens, nutrition, claims, warnings and certification marks come from the client's compliance or regulatory lead as a signed, version-numbered copy source. The studio sets exactly what that source says and checks the artwork against it, word for word. Rules are specific and differ by market. For example, the European Commission's food information pages note that mandatory food information in the EU must be printed with an x-height of at least 1.2 mm, or 0.9 mm where the largest surface is under 80 square centimetres. Certification marks have their own rules: the Forest Stewardship Council explains that applying its label to products requires chain of custody certification, which a promotional licence does not give. Ask the client and printer to confirm what may be printed.

What does a prepress check cost compared with a reprint? A worked example

Take a small branding studio printing 2,000 café menus. A full prepress check on the exported PDF takes about 15 minutes. At an internal cost of 1,300 an hour, that is about 325 in studio time. In our illustrative case the menus went out without a check, the prices were set in rich black, and every number printed with a coloured fringe. The reprint cost 14,500. One reprint pays for roughly 44 checks.

The same studio then compared three quotes for 5,000 cup sleeves. The cheapest headline price was not the cheapest real price once a proof and delivery were added, and it missed the needed-by date. The figures below are illustrative, in Indian rupees, from a fictional studio's sample data.

What are the most common prepress mistakes?

Most reprints come from a short list of avoidable faults. Each has a visible sign, and each is fixed in the file in minutes if someone looks before the file leaves.

• No bleed: a background stops exactly at the trim line.
• Text in the trim margin: words too close to the edge get clipped.
• Small text in rich black: fuzzy, coloured edges on body copy.
• Accidental overprint: a white logo vanishes on press.
• One colour defined two ways: two slightly different greens side by side.
• RGB images in a CMYK-only job: dull, shifted colour on the proof.
• Low-resolution images: soft or blocky at final size.
• Old dieline: folds and glue flaps in the wrong place.
• Dieline printing: cut lines visible on the finished pack.
• Wrong version sent: a file from the working folder instead of the print-ready one.

How do you know your prepress process is working?

Measure right-first-time artwork: the share of files that pass their first prepress check with no issues. Log the first check only. If you log the re-check after a fix, every file passes and the number tells you nothing. Read the notes on failed checks once a month and add any repeated cause to your checklist. Track reprints alongside it: reprints per print job, and the net cost after anything recovered from printers or couriers.

Keep the habit visible. A one-page checklist beside the screen, a column in your job tracker, and one person who did not build the file doing the second check on packaging and long runs. If you want a ready-made system, The Design Studio Production and Hand-off Kit from Bodhih Training includes a prepress checklist, a first-check log and a dashboard. Attention to detail can also be trained and measured: AssessAll's Attention to Detail and Error Checking assessment gives a new artworker a baseline, and Jobulary's guide to if-then plans helps turn 'check every file' into a habit that sticks.