Print · 7 min read · June 2026
CMYK, bleed and the three files every printer wants
Most reprints I hear about are not a design problem. They are a file problem — the wrong colour mode, no bleed, or a format the press cannot open. None of this is complicated once you know the three words that matter.
A screen shows colour as light — red, green and blue mixed together. A press lays down colour as ink — cyan, magenta, yellow and black mixed together. Those are two different systems, and a file built for one does not automatically translate to the other. Get this wrong and the fix costs you a full reprint, not a five-minute edit.
You do not need to become a printer to avoid the common mistakes. You need three words and one habit.
01
CMYK, not RGB
Screens mix light (RGB) to make colour; presses mix ink (CMYK). A bright screen blue or green often prints duller than expected because it falls outside the CMYK range. Converting the file to CMYK before you approve it shows you the real result, not a surprise.
Check: does the file say RGB or CMYK in its colour settings?
02
No bleed means white edges
If your artwork stops exactly at the trim line, a fraction-of-a-millimetre shift in cutting leaves a thin white sliver on one side. Extending the background 3mm past the edge — bleed — makes that shift invisible.
Check: does colour or imagery extend past the edge of the page, or stop dead at it?
03
PNG is not a print format
A PNG or JPG exported from a phone or a slide deck is built for screens: RGB colour, no bleed, often low resolution. It can look fine in an email and still print blurry or with the wrong colours.
Check: can you open the file and zoom to 300% without it turning to mush?
04
Fonts need outlining or embedding
If you send an editable file without outlining the text or embedding the font, the printer's software silently substitutes a default font — and your headline changes without anyone deciding it should.
Check: ask whether fonts are outlined (vector) or embedded in the PDF.
05
Low resolution photos
A photo that looks sharp as a small thumbnail can turn to visible pixels once it is stretched across a full page. 300 DPI at final print size is the safe minimum; anything pulled from a website or WhatsApp is usually well below that.
Check: is the photo's actual pixel size big enough for 300 DPI at the size it will print?
06
One file, three purposes, three exports
The file you approve on screen, the file that goes to press and the file you forward to a client on WhatsApp are not the same thing. Trying to use one export for all three is where most of these problems start.
Check: do you have a print PDF, an editable source, and a screen-friendly export — separately?
The three files, in one line each
A print-ready PDF in CMYK with 3mm bleed and crop marks for the press. An editable source file (AI or layered PDF) in case anything needs a last-minute change. A flat, screen-friendly export — sRGB, no bleed — for anyone who just needs to look at it on a phone.
Ask for all three up front. It costs nothing extra and saves the "can you also send it as—" email.
Words worth knowing before you brief a printer
You will not be quizzed on these, but using them correctly gets you a faster, more accurate quote.
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Bleed
Artwork extended 3mm past the trim line, so a small shift in cutting never leaves a white sliver at the edge.
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Crop marks
Small guide lines outside the artwork showing the press exactly where to cut. Standard on any print PDF.
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DPI / resolution
300 DPI at final print size is the safe default. Anything lower and photos come out visibly soft.
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Spot colour
A single pre-mixed ink (a Pantone) used for exact brand colour matching instead of the four-colour CMYK mix.
If a printer hands your job back asking for any of this, it is not them being difficult — it means the file genuinely was not ready, and they just saved you a bad print run.
Related reading
Print job coming up?
Send me the artwork and I'll tell you if it is press-ready, or prep the CMYK, bleed and crop-mark version myself.