Supplying print-ready artwork

Most print problems are file problems, and the same six recur.

1. Bleed and safety margin

Any image or colour reaching the edge of the finished piece must extend 3 mm beyond the trim line. Cutting has a tolerance, and without bleed some copies will show a white sliver.

Equally, keep text at least 4 mm inside the trim line. Text placed close to the edge will be cut on some copies of the run.

2. Colour space

Print uses four process inks; screens use three light primaries. Files supplied in the screen colour space are converted by the printer, and the conversion changes the appearance.

Convert deliberately rather than letting the printer do it, and where a brand colour must be exact, specify a spot ink and accept the cost.

3. Resolution

300 dpi at final printed size for photographs, 1,200 dpi for line art. An image that looks acceptable on screen at 72 dpi will be visibly soft in print.

The common error is enlarging a web image. A 600-pixel-wide photograph cannot be printed at 100 mm width acceptably.

4. Fonts

Embed them or convert text to outlines. A file referencing a font the printer does not have will be substituted silently, and the first anyone knows is when the proof arrives with different type.

Conversion to outlines removes the risk entirely and prevents last-minute text edits, which is usually an acceptable trade.

5. Rich black

Text printed in a single black ink looks grey on large areas. Large black areas need a build of several inks; small text should stay single black to avoid registration problems producing coloured fringes.

Getting this backwards is one of the most visible amateur signals in print.

6. File format and proofing

Supply a print-ready PDF at the specification the printer states, with the correct standard, bleed included and marks as requested.

Then request a proof. A digital proof catches content errors; a physical proof catches colour. For any run above a few hundred copies, or any colour-critical job, the physical proof is worth the cost and the day.

The checklist before sending

Bleed present, safety margin respected, colour space converted, images at 300 dpi at final size, fonts embedded or outlined, blacks built correctly, and one final read of the copy by somebody who has not seen it before.