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The Print Shop's Guide to AI Prepress · Preflight

The 7 things wrong with almost every customer file

Files arrive at the counter looking fine on screen. Screens lie. Here are the seven problems hiding in most customer files, why each one ruins a press run, and what the fix actually is — whether a person does it or software does.

1. RGB color

Canva, PowerPoint, phone photos — all RGB. Your press prints CMYK, and the conversion moves colors whether you manage it or not. Unmanaged, that electric blue goes purple and the bright green goes muddy. Fix: convert with a press profile before anything else touches the file, so what proofs is what prints.

2. Fonts that aren't embedded

An unembedded font means the RIP substitutes whatever it has — and the first you hear of it is a customer holding a card set in Courier. Fix: embed everything; where licensing blocks embedding, outline it.

3. No bleed

Art that runs to the page edge with zero past it guarantees white slivers at the cut — no cutter trims to zero tolerance. Fix: 0.125" of bleed on every trimming edge. When the customer can't resupply, the edge artwork can be mirrored outward to build bleed that survives the cut (that's what Plateroom does automatically).

4. Hairline rules

Lines thinner than about 0.25pt render on screen and vanish on plate — or print on one press and not the next. Fix: bump anything thinner up to a printable weight.

5. Low-resolution images

A logo screenshotted off a website is 72 DPI; print wants ~300 at final size. On paper that's the difference between crisp and fuzzy-with-jaggies. Fix: upscale toward 300 where the pixels support it, rebuild logos as vector where they don't, and flag anything too far gone for a human call — never silently print mush.

6. Overprint surprises

Overprint settings buried in a file can make white text disappear into a background or double-print inks into mud — invisible until you simulate it or run the job. Fix: render every page with overprint simulation on and off, compare, and flag real differences for an operator's eyes. Guessing here causes reprints.

7. Built at the wrong size

The order says 5×7; the file is 8.5×11 letter with the design floating in the middle. Cut a 5×7 window out of that and you clip the art. Fix: decide deliberately — scale the design to the stated size, or if the ink genuinely fits inside the finished size, set the cut lines and trim the empty margin. The wrong default ruins the job either way, which is why this one deserves the most care.

The pattern across all seven: screens forgive, presses don't. Preflight is just the discipline of finding out on the screen instead of on 500 printed sheets.

Plateroom does everything in this guide automatically. Drop the file, type the job like a work order, download the plates. First 20 jobs free.

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