Rich black

Pure black in print means 100% K – just the black ink. On large areas it often looks dark gray rather than deep black. That's why a little cyan, magenta and yellow is added for a deep black: so-called rich black.

Which mix is common?

A widely used example is C 60 · M 40 · Y 40 · K 100. The total of all inks (total ink coverage) must not get too high – many printers state a limit of around 300%, otherwise the ink dries poorly or sets off. Best use your printer's recommendation.

What rich black is for – and what not

• Yes: large black areas, backgrounds, thick bars.
• No: text, especially small type, and fine lines. The four inks are never printed in perfect register – small type gets colored fringes and looks blurry. Text belongs in 100% K.

And if the file is RGB?

Black from RGB (#000000) becomes a four-color black when converted, depending on the profile – text included. That's why PreflightPilot deliberately converts gray and black from RGB colors to pure K, so type stays sharp. Large rich-black areas are best set up deliberately in your layout program.